My lovely cousin had the audacity to get married to a great guy, host a rocking party, and gather most of my awesome family together—on Halloween weekend. (Britt: I’d take your wedding over Halloween any day. Same time next year? Invite the whole family to the first anniversary party?) Fantastic time, fantastic party, but no costume, no party, no fun-sized Snickers bars… Something had to be done. My hastily pulled-together Where’s Waldo costume on the actual day was just recognizable to be awkward without being all-out enough for people to comment (where’s a red and white striped hat when you need it?), so that didn’t cut it. Clearly the solution would be a baked good—it usually is.
I was inspired by this video but wanted different flavors of cookies instead of just food-coloring: vanilla, chocolate, and pumpkin. So I decided to invent, shop for, mix, assemble, and bake these three-layer cookies in my hour and a half break between work and Spanish class. Note: if one is not crazy, it may be in one’s best interest to allow slightly more prep time.
For a rushed and somewhat MacGyvered cookie, these turned out surprisingly well. There is, however, a distinct difference in texture between the pumpkin layer and the other two—not a huge issue but an interesting chemical story.
Aside from the spices, the basic recipes are very similar: flour, butter, salt, sugar. But there is one important difference: the pumpkin cookies use pumpkin puree instead of the eggs in the vanilla/chocolate recipe. By looking at the role that eggs play in baking, we can figure out how the pumpkin replaces it.
In most cookies, eggs provide moisture (they’re mostly water), fat for richness, and, importantly, proteins for stability. When you cook an egg by itself, the heat transforms it from runny and liquid to firm and solid (it’s all thanks to proteins—read this for the details). The proteins start out with each one balled up around itself, but the heat makes it spread out into a long chain that connects with other proteins in a strong network. This same basic process happens in baked goods, but instead of the network forming only around the water in the egg, it scaffolds all of the other ingredients and helps the final product hold its shape.
This function is hard to replicate, and coming up with a good egg substitute is a challenge in vegan baking. Pumpkin, though, does a pretty good job. Like in most fruits and vegetables, the cell walls in pumpkin contain pectin, which you may know as an important part of jam. Pectin is mostly polygalacturonic acid (illustrated below, in case you can’t just picture that off the top of your head), and it exists in long chains. Like other long chains we’ve encountered (gluten and egg proteins), the pectin polymers bond together to make a network and add stability. In the plant, this helps cell walls stay firm and also binds cell neighbors together. In cooking, it can play a similar structural role—which is exactly why we want it in these cookies. While pectin is great, it’s not quite as strong as the egg protein network, which is part of why the pumpkin cookies are softer than the vanilla and chocolate sections.
There’s another important molecule in pumpkin that plays a role in cookie structure—starch. It’s similar to pectin, in a way. Starch is made up of two different kinds of long chains of sugars: amylose is a linear or helical chain of glucose molecules, while amylopectin is branched. Starchy vegetables like potatoes, sweet potatoes, and winter squashes (including pumpkin!) contain small, hard nuggets of starch molecules. When they are heated, the starch granules absorb water and swell up, packing closely together. Think about those little sponges or washcloths you can get that are initially compressed tightly but expand once they’re in water (look for Disney’s Magic Towel if you don’t have any idea what I’m talking about). If you put a bunch of those in a glass of water and let them all expand at once, they press against each other and against the sides of the glass, making a pretty solid unit. Starch works basically the same way. It expands within the networks of gluten and egg or pectin and adds structure and solidity to the final product.
Candy corn cookies
These are icebox cookies, but not like any other icebox cookies I’ve seen. It’s three separate cookie doughs pressed together into a three-flavor combination of all of the best kinds of cookies. They don’t always turn out looking quite like candy corn, but I promise they’re way more delicious.
Yield: about 50 cookies
Chocolate and vanilla cookies
1 c. butter, softened
1 ½ c. granulated sugar
½ c. firmly packed brown sugar
1 T. vanilla extract
½ t. baking soda
½ t. salt
2 ¾ c. flour
¾ c. cocoa powder
Beat together the butter, sugars, and vanilla. Add the eggs, one at a time, then the baking soda and salt. Split the dough into two bowls. To the vanilla batch, mix in 1 ¾ c. flour. To the chocolate, mix in 1 c. flour and the cocoa powder.
½ c. butter, softened
1/3 c. powdered sugar
1 ¼ c. flour
1/8 t. salt
½ c. pumpkin puree
½ t. vanilla extract
¼ t. ground cinnamon
1/8 c. ginger
Red and yellow food coloring (optional)
Beat the butter until creamy, then add powdered sugar. Add the flour and salt, then the pumpkin puree. Mix in the spices. If you want the orange color to be extra vibrant, add food coloring.
Line a loaf pan with tin foil. Press the pumpkin dough into the bottom of the pan, then the chocolate and vanilla. Each layer should be distinct and as level as possible.
Refrigerate the dough for at least 8 hours (or, you know, however long you have, because you really don’t have all day to wait for these cookies). When you’re ready to bake them, preheat the oven to 350 degrees F. Pull up on the edges of the tin foil to remove the dough block from the loaf pan. Cut a slice from the end about ¼ inch wide, then cut the slice into triangles containing each of the three colors.
Bake for about 20 minutes, or until the vanilla sections are browned.
The dough will keep in the fridge for about a week or in the freezer (well-wrapped, of course) for a few months. Which means that once you make the dough, you have awesome cookies only a few slices away at all times. Ideal.