Playdate Special: Marshmallow Cake Towers

Homemade marshmallows are wonderful to make with kids. They probably have no idea what marshmallows are made of -- most grownups don't either. (The answer: gelatin, sugar syrup, and flavoring. The bags at the store also have artificial color, flavor, and other stuff.)

Spring vacation week is a great time for some kitchen science with the kids. I have one recipe for you here, made with egg whites, and an egg-free version coming tomorrow. Whip up a batch or two, and have a family taste test -- how do homemade marshmallows stack up against store-bought sweets? (Here's our review.)

Homemade marshmallows are divine enjoyed alone, but they are easy to turn into deceptively elegant treats. Today we have towering cakes that will thrill your kids (and you!), and tomorrow I have a dessert that will give the most skeptical grownups a new appreciation for this simple confection.

Don't be intimidated by the length of the instructions. Once you try it, you'll realize just how easy it is. You need only two pieces of special equipment: a candy thermometer and a standing mixer. Don't attempt this by hand. You can try using a handheld mixer, but it might not be up the task.

Marshmallow Cake Towers

This marshmallow recipe is adapted from Smitten Kitchen. The marshmallows need to be made at least a few hours ahead; leftover marshmallow can be stored in an airtight container for a few days.

For marshmallows:
canola oil
1/2 cup confectioners sugar, divided
3 1/2 envelopes unflavored gelatin (such as Knox)
1 cup cold water, divided in half
2 cups sugar
1/2 cup light corn syrup
1/4 teaspoon salt
2 egg whites
1 tablespoon vanilla extract
1/4 cup cornstarch

For cakes:
9x13 yellow cake, baked and cooled (use your favorite recipe, from scratch or a box)
1/2 cup fruit preserves (any flavor -- I used cherry)
fresh fruit, chopped, for garnish (I used mango, strawberry, and kumquat)

To make marshmallows:
Lightly oil the bottom and sides of a 9x13 pan and dust with 1/4 cup confectioners sugar, shaking out excess. In the bowl for your mixer, pour in 1/2 cup of cold water and sprinkle gelatin on top. Let it sit so the gelatin softens and blooms, about 15 minutes.

In a small saucepan, combine remaining 1/2 cup of water, sugar, corn syrup, and salt. Clip a candy thermometer to the side. Stir over low heat until the sugar is dissolved. Increase the heat to medium heat and bring to a boil, without stirring, until it reaches 240°F (this can take 10-15 minutes). Take the pan off the heat. Carefully pour the sugar mixture over the gelatin in the mixer bowl and stir to dissolve the gelatin. Using the mixer, beat on high speed until the mixture is white, thick, and about tripled in volume (about 6-8 minutes).

In a separate bowl, with clean beaters, beat egg whites until they hold stiff peals. Beat whites and vanilla extract into the sugar mixture until combined. Pour the mixture into the prepared pan. Combine remaining 1/4 cup confectioners sugar and cornstarch and sift over the top. Set it in the refrigerator, uncovered, for at least three hours and up to one day. Once the marshmallow has set, you can remove it from the pan by loosening the edges with a thin knife and peeling the marshmallow block out, or inverting the pan.

To assemble cakes:
Level the cake. Use a cookie cutter (round, square, or diamond work well) to cut out cake pieces. Clean and dry the cookie cutter, dip it into confectioners sugar, and use it to cut out identical marshmallow pieces. Spread fruit preserves on top of each piece of cake. Place marshmallow cutouts on top of preserves, then top with fruit.