God, I love those things. I remember pocketing more than one at a time as a kid—a secret, bonus dessert on my way out. You don't really see them much anymore, though locals will note that the Chateau in Waltham still has them, individually wrapped instead of in an open, shallow bowl as in the days of old.
I recently came across a recipe for homemade buttermints in the latest issue of Organic Gardening magazine, and I was all, wait a minute, you can make them yourself? Apparently I was holding on to the childhood notion that they were made by fairies in some mystical realm, that these were something mere mortals could never achieve. Luckily (and dangerously) for me, they are easily achievable, and I had all four ingredients in the house.
The flavor of these buttermints is spot-on, but the texture is a little different than what I remember. Even though the technique involves setting the mints out to dry overnight, mine never got hard and chalky. They tasted like little bits of peppermint frosting that had crisped delicately on the outside, but stayed soft on the inside. They literally melt in your mouth. I guess if you left them out in the open air long enough, they would harden eventually. I tried to do an experiment to see how long it would take for them to harden fully, but I kept eating all the experimental ones. And then all the controls. (My scientific method has some flaws.)
You can tint these whatever hideous colors your heart desires with drops of food coloring, but I like mine the color of butter.
1/2 cup (1 stick) unsalted butter, softened
4 cups confectioner's sugar
2 Tbsp. heavy cream
1/4 tsp. peppermint extract, plus a few extra drops to taste
Line two large baking sheets with waxed paper. In a large mixing bowl, whip the butter with an electric mixer until creamy. Blend in the confectioner's sugar 1 cup at a time on low, adding the cream and peppermint extract with the last cup of sugar. Scrape down the sides of the bowl, increase the speed, and whip until well mixed. Taste and adjust the flavoring if you like.
Dust the counter with confectioner's sugar. Divide the dough into golf-ball-sized pieces and roll each ball into a long rope about 1/2-inch thick. Use a sharp knife or a bench scraper to cut the rope into small pillows. Transfer the mints to the baking sheets. Let the mints dry in a cool, dry place overnight. Store in an airtight container in a cool place for up to 2 weeks. Makes about 200 mints.