More and more kitchen gadgets, such as spatulas and pastry brushes, are made of silicone.

	Silicone ware can bend, roll, pop into shape, withstand oven temperatures and is nonstick and refrigerator, freezer, microwave and dishwasher safe, making it ideal for baking. (Pam Panchak, Post-Gazette photo with food styling by Marlene Parrish)

Silicone ware bends, rolls, can be turned inside out and pops back into shape. Dropped, it takes a little bounce.

But what shocks and amazes are the baking pans and muffin "tins," which look and feel just like rubber. Not only can they withstand oven temperatures up to 500 degrees, they also are refrigerator, freezer, microwave and dishwasher safe, nonstick and unharmed by metal utensils. Can this be true? Only testing them in our own kitchen could make us believers.

We assembled various red and blue KitchenAid silicone baking pans -- cupcake, mini-muffin, angel food cake, Bundt and bread, along with heart-shaped, round and square cake pans. First time out, the tests would be about the bakeware, not the food.

We chose cake, muffin and cornbread mixes and frozen bread dough. If these turned out OK, we'd chance making desserts and bread from scratch.

The most important thing we learned is how to handle the flexible pans when transferring them into and out of the oven. Picking up a pan full of dough or batter by grasping its sides is not an option; the pan bends into a saucer-like shape and the batter flows to the middle.

The trick is to think like a pizza maker. Use a flat METAL cookie sheet, slide it under the pan like a pizza peel, place the pan on the oven rack, and with a quick backward motion, jerk the cookie sheet out from under. The pan then bakes directly on the oven rack.

To remove the baked product, slip the cookie sheet under the pan to lift it out. Then, using the cookie sheet again as a peel, slide the pan onto a rack to cool. The challenge is more mental than physical.

Our experiments:

The square baking pan -- Using a box of prefab brownie mix, we're off to an easy start. We got used to the pizza-peel-jerk motion and was relieved that the pan didn't melt on the oven rack. The brownies were cut in the pan using a dull bread knife.

The mini-muffin pan -- KitchenAid's nonstick wire rack, called a "sled," supports this flexible pan. No need for a cookie sheet peel here. We were intentionally sloppy spooning cornmeal batter into the cups in order to test the washability of the pan. The muffin-ettes were perfect, with high domes and crunchy sides. A push on the bottom of each cup popped the muffin out, making "easy release" an understatement. Later, the pan cleaned up with the swish of a soapy brush. KitchenAid's sled is so attractive, next time I'll be neater so that I can bake and serve right from the pan, resting on its sled.

The angel food, heart-shaped and large and mini-loaf pans -- All picture-book perfect, with easy release and cleanup.

The Bundt pan -- To experiment, we made a double batch of blue Jell-O and poured it into the 8-cup blue Bundt pan and placed it on a baking sheet with sides. Trying to wrestle the sloshing waves into the fridge was like Don Knotts on a trampoline. When the blue menace finally gelled, it was difficult to release from the pan, even when dunked into a sink full of hot water. Moral: Do not try this at home. There's a reason they call this stuff BAKE ware.

The round, deep cake pan -- Now for the big test. We picked a worst-case scenario -- an upside-down cake made from scratch -- a sticky brown sugar and butter topping with dried apricots, prunes and cherries and a batter of dense yellow cake. The pizza peel method loaded the cake onto the oven shelf and assisted in taking it out. The gooey cake released beautifully.

Silicone bakeware does what it says it will. The biggest problem now is to decide what to keep and which twin metal pans to give away or send off to storage. Temporarily, we've rolled up the bigger silicone pans, secured them with rubber bands and stood them in a cabinet.

How silicone works

Here the science writer takes over.

There are three basic kinds of rubber: natural rubber, which comes from latex, the sap of the tropical tree Hevea brasiliensis; synthetic rubber, which comes from a chemical plant; and silicone rubber, which comes from, well, a different chemical plant.

The last two were dreamed up by chemists to duplicate some of natural rubber's unique properties and improve upon others. A synthetic rubber called neoprene was first marketed by DuPont in 1931, while a wide variety of silicone rubbers have been manufactured by General Electric and Dow Corning since the 1940s. These two man-made products inherited the silly name rubber from the natural material, which was so christened by the English chemist and clergyman Joseph Priestley in 1770, when he found that it would rub out pencil marks.

Unfortunately, in recent times the word silicone has been implanted, so to speak, in the public's mind in but a single context: cosmetic augmentation. But silicones are a remarkably versatile family of chemical compounds with hundreds of uses.

In culinary applications, the French fiberglass-reinforced silicone baking-pan liner called Silpat has been used in professional kitchens since it was introduced in 1982. But silicones have only recently invaded the American home kitchen in many forms, all approved by the Food and Drug Administration for repeated contact with food.

Today, the whole baking pan, not just its liner, is made of silicone. Before going on, it's necessary to straighten out some terminology, because the words silicone and silicon are so often mistakenly interchanged.

Silicon (no e) is a chemical element, the second most abundant element on Earth (after oxygen). A rock-hard, brittle material, it would make the world's worst cake pans, not to mention surgical implants.

However, silicon the element is a semiconductor and therefore immensely valuable in the form of chips or microprocessors in computers and hundreds of other electronic devices. That's why the high-tech region around San Jose, Calif., is called Silicon Valley. (It is to be carefully distinguished from Hollywood, which has been dubbed Silicone Valley for reasons that need not be explained.)

Silicones, on the other hand, are chemical compounds that, like the natural and synthetic rubbers, are polymers, meaning that their molecules consist of long chains made up of thousands of smaller molecules tied together. Silicones can range from liquids (used in brake fluids and water-repellent sprays) to gels (in breast implants) to greases (in lubricants and lipsticks) to elastomers or rubber-like materials (in Silly Putty, Superballs, refrigerator door gaskets and, now, kitchenware).

Silicone bakeware has a useful set of properties. First, the material is inherently translucent, so a veritable kaleidoscope of bright colors can be incorporated into the products. It can also withstand high temperatures without melting (i.e., without its molecules flowing apart from one another) because the molecules are very long and tightly intertwined, like a cold, leftover plate of Spaghetti with Glue Sauce.

That's also why you can take the bakeware directly from the oven to the freezer or vice versa without any fear of cracking; the molecules, while individually flexible, are so rigidly fixed in place that the material can't expand or contract very much with changes in temperature.

Properties for baking

Silicones don't absorb microwaves, but like all microwave-safe utensils they can get hot in the microwave oven from contact with the heated food. Because silicones are chemically inert, the pans are dishwasher safe; caustic detergents can't touch them. Also because of their nonreactivity, they are more or less nonstick; cakes and muffins release easily -- most of the time -- since you can flex the pans to pop them out.

The reason the Jell-O mold wouldn't release is because the silicone is a heat insulator.

Any disadvantages? Being electrical insulators (one of the most important properties of silicone rubbers in many other applications), they are subject to static electricity and may collect dust in the pantry between uses. And their floppiness can be disquieting. Using a rimless baking sheet used as a peel is a good trick.

Caveat emptor department: As with everything else, there are high and low qualities of silicone bakeware. Remember that silicone isn't a single chemical material.

Dow Corning, for example, sells dozens of different silicone formulations with different properties, for fabricators to use in molding their commercial products. Some may not be as heat-resistant as others, so check the maximum temperature ratings on the labels. They can range from 450 degrees to 675 degrees for the silicone trivet pads.

Other silicone products

Silicone bakeware, including KitchenAid, is carried by retailers nationwide.

You can find it at department stores, in catalogs and at kitchenware stores, such as Sur La Table and Williams-Sonoma.

Other products include madeleine, brioche and fluted tart molds. Durable spatulas won't chip, crack or lose their shape and can withstand heat up to 450 degrees. Look for whisks, bowl scrapers, kitchen mitts and pot holders that double as trivets.

TART FRUIT UPSIDE-DOWN CAKE

Any fruit topping can be used as long as the amount does not exceed 2 cups. The cake can be baked in a straight-sided metal or silicone cake pan or in a 10-inch cast-iron skillet. If using a skillet, the total baking time is reduced by 10 or 15 minutes.

• Topping:
  
• 4 tablespoons unsalted butter
  
• 3/4 cup light brown sugar
  
• 2 cups mixed dried fruit (apricot and prune halves, dried cherries or dried cranberries)
  
• Cake:
  
• 1 1/2 cups flour
  
• 1 1/2 teaspoons baking powder
  
• 3 tablespoons cornmeal
  
• 1/2 teaspoon salt
  
• 8 tablespoons unsalted butter, room temperature
  
• 1 cup granulated sugar, plus 2 tablespoons for egg whites
  
• 4 large eggs, separated
  
• 1 1/2 teaspoons vanilla
  
• 2/3 cup milk

For the topping: Spritz a 9-by-3-inch round cake pan with baking spray. Melt 4 tablespoons butter in a medium saucepan over medium heat; add brown sugar and cook, stirring occasionally, until mixture is foamy and pale, 3 to 4 minutes more. Pour mixture into prepared cake pan; swirl pan to distribute evenly. Arrange fruit in a pleasing pattern. Set aside.

For the cake: Adjust oven rack to lower-middle position; heat oven to 350 degrees. Whisk flour, baking powder, cornmeal and salt together in medium bowl; set aside.

Cream butter in large bowl with electric mixer at medium speed. Gradually add 1 cup sugar; continue beating until light and fluffy, about 2 minutes. Beat in yolks and vanilla (scraping sides of bowl with rubber spatula if necessary); reduce speed to low and add dry mixture and milk, alternately in 3 or 4 batches, beginning and ending with dry ingredients, until batter is just smooth.

Beat egg whites and 2 tablespoons sugar in large bowl at low speed until frothy. Increase speed to medium-high; beat to soft peaks. Fold one-quarter of beaten whites into batter with large rubber spatula to lighten. Fold in remaining whites until no white streaks remain. Gently pour batter into pan and spread evenly on top of fruit, being careful not to disperse fruit. Bake until top is golden and toothpick inserted into cake center (not fruit, which remains gooey) comes out clean, 60 to 65 minutes.

Rest cake on rack for 2 minutes. Slide a spatula around the edge of the cake to loosen it, then place serving platter over the cake and give it a flip, inverting it and turning it upside down. Remove cake pan. If any fruit sticks to pan bottom, remove and reposition it on top of the cake.

Serves 8 to 10. Best served warm with softly whipped cream.

Adapted from Cooks Illustrated