When I was a baker at a conference center on Star Island, twelve miles off the coast of New Hampshire, I learned how to make this kind of cookie from one of the best bakers I know, Mandy Lamb. She would put different ingredients in the cookie each day or each week and have people try and guess what the random secret ingredients were.
Because we were on an island in New England, when storms blew in, we were trapped. No one traveled on the island, and, more important, no boats with food on them came our way, either. We had to get creative and use what we had on hand. We might not have had enough chocolate chips to make chocolate chip cookies, but if we threw in other mix-ins as well, the seven hundred some guests would never notice the shortage of one ingredient – and the cookies would always feel brand new, because they were different every time. I found that after many batches that my favorite compost cookies had my favorite snacks in them: chocolate and butterscotch chips, potato chips, pretzels, graham crackers, and coffee (grounds).
Compost cookies always turn out great in my mother’s kitchen because she infamously has a hodgepodge of mix-ins, none in great enough quantity to make an actual single-flavored cookie on its own. My brother-in-law calls them “garbage cookies”; others call them “kitchen sink cookies.” Call them what you want, and make them as we make them at Milk Bar, or add your own favorite snacks to the cookie base in place of ours.
2 sticks butter (16 tablespoons), at room temperature
1 cup granulated sugar
2/3 cup light brown sugar, tightly packed
2 tablespoons corn syrup
1/2 teaspoon vanilla extract
1 1/3 cups flour
1/2 teaspoon baking powder
1/4 teaspoon baking soda
1 teaspoon kosher salt
3/4 cup chocolate chips
1/2 cup mini butterscotch chips
1/2 cup recipe graham crust (see below)
1/3 cup old-fashioned rolled oats
2 1/2 teaspoons ground coffee
2 cups potato chips
1 cup mini pretzels
1 1/2 cups graham cracker crumbs
1/4 cup milk powder
2 tablespoons sugar
3/4 teaspoon kosher salt
1/2 stick (4 tablespoons), melted butter
1/4 cup heavy cream
For the Compost Cookie:
1. Combine the butter, sugars, and glucose in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 2 to 3 minutes. Scrape down the sides of the bowl, add the egg and vanilla, and beat for 7 to 8 minutes.
2. Reduce the speed to low and add the flour, baking powder, baking soda, and salt. Mix just until the dough comes together, no longer than 1 minute. (Do not walk away from the machine during this step, or you will risk overmixing the dough.) Scrape down the sides of the bowl with a spatula.
3. Still on low speed, add the chocolate chips, butterscotch chips, graham crust, oats, and coffee and mix just until incorporated, about 30 seconds. Add the potato chips and pretzels and paddle, still on low speed, until just incorporated. Be careful not to overmix or break too many of the pretzels or potato chips. You deserve a pat on the back if one of your cookies bakes off with a whole pretzel standing up in the center.
4. Using a 2 ¾ ounce ice cream scoop (or a 1/3 cup measure), portion out the dough onto a parchment-lined sheet pan. Pat the tops of the cookie dough domes flat. Wrap the sheet pan tightly in plastic wrap and refrigerate for at least 1 hour, or up to 1 week. Do not bake your cookies from room temperature— they will not bake properly.
5. Heat the oven to 375°F.
6. Arrange the chilled dough a minimum of 4 inches apart on parchment- or Silpat-lined sheet pans. Bake for 18 minutes. The cookies will puff, crackle, and spread. After 18 minutes, they should be very faintly browned on the edges yet still bright yellow in the center. Give them an extra minute or so if that’s not the case.
7. Cool the cookies completely on the sheet pans before transferring to a plate or an airtight container for storage. At room temp, cookies will keep fresh for 5 days; in the freezer, they will keep for 1 month.
For the Graham Crust:
1. Toss the graham crumbs, milk powder, sugar, and salt with your hands in a medium bowl to evenly distribute your dry ingredients.
2. Whisk the butter and heavy cream together. Add to the dry ingredients and toss again to evenly distribute. The butter will act as glue, adhering to the dry ingredients and turning the mixture into a bunch of small clusters. The mixture should hold its shape if squeezed tightly in the palm of your hand. If it is not moist enough to do so, melt an additional 14 to 25 g (1 to 1½ tablespoons) butter and mix it in.
3. Eat immediately, or deploy as directed in a recipe. The crust is easiest to mold just after mixing. Stored in an airtight container, graham crust will keep fresh for 1 week at room temperature or for 1 month in the fridge or freezer.