How to Make It
Preheat oven to 350°F.
Combine the first 7 ingredients through salt in a large bowl.
Place butter and sugar in the bowl of a stand mixer. Using the whisk attachment, beat over high speed for 3 minutes, or until fully incorporated. Add molasses and egg, and continue beating for 1 to 2 minutes, or until combined.
Turn mixer down to low and slowly add dry ingredients.
Divide the mixture into 2 tablespoon balls and then form to the inside of a well-greased muffin tin. Bake for 12 minutes, or until cookies are set but still a little soft in the center.
Remove the baking sheet from the oven and use a spoon, or the top of a spice container, to press the center of the cookies down, creating a cup shape. Let cookies rest until cooled.
Meanwhile, melt chocolate chips in the oven, according to the package directions. Spoon a bit of melted chocolate into the cups and spread evenly around the inside.
When chocolate is set, fill cups with milk, and set out for Santa.