Hot oven to 350. Lightly grease twelve 1 cup capacity mini-bundt pans. (If you only have 1 pan with 6 wells, the batter can remain at room temperature while the first batch bakes.) You can also use regular 1/2 cup capacity muffin tins using 1/3 cup batter per well. For batter: In a large bowl with an electric mixer on medium low speed, beat butter, sugar, cocoa, pie spice, baking powder and baking soda unitl creamy, gradually increasing speed to high. Add eggs, one at a time and beat until mixture is fluffy. On low speed, beat in pumpkin, milk and vanilla (mixture will look curdled). Gradually add flour, beating just until blended. Fill each prepared well with 2/3 cup batter (if using separate tins). Smooth tops. Bake 18 to 20 minutes until a pick inserted in center comes out clean. Cool in pan on a wire rack for 10 minutes. Invert pan on rack and tap to release cakes. Let cool completely. Place rack over a waxed paper lined baking sheet. For frosting: In a medium saucepan, bring brown sugar, butter and milk to a gentle boil. Stir until butter melts, sugar dissolves and mixture is smooth. Gradually beat confectioners' sugar and vanilla into hot mixture. Remove from heat and beat in red and yellow food color until frosting is pumpkin orange. (You may need to add some more food coloring.) Spoon frosting over cakes so it runs down sides, letting some cake show near the bottom. If frosting becomes too thick, stir over low heat or transfer to a microwave safe bowl and microwave on medium (defrost) until the right consistency. Cut wafer cookies in half crosswise and insert in center hole of cakes for "stems". (Frosing will help them stick.) Cover with plastic wrap and store at room temperature up to 3 days.