Chocolate Sandwich Cookies
["1/2 c. soft butter", "1 c. sugar", "1 egg", "1 tsp. vanilla", "1 c. milk", "1/2 tsp. baking powder", "1 1/2 tsp. soda", "1/2 c. cocoa", "2 c. flour", "1/2 tsp. salt"]
["Mix together in order as given; beat until smooth.", "Drop by teaspoon onto greased cookie sheet. Bake seven minutes at 400\u00b0."]
["butter", "sugar", "egg", "vanilla", "milk", "baking powder", "soda", "cocoa", "flour", "salt"]