Turn old-fashioned black walnut cake into cupcakes. The cupcakes are gently spiced with cardamom while walnut extract boosts the nuttiness. They're easy to tote so keep them in mind for summer picnics.
Heat oven to 350 degrees F. Line 12 cups in standard-size muffin pan with cupcake liners. Whisk together flour, baking powder, cardamom and salt in a bowl.
Beat butter and sugar in large bowl until light colored and smooth, 2 minutes. Add eggs, one at a time, along with extract, beating well after each egg, On low speed, add flour mixture. Stir in nuts. Divide batter among liners, a rounded 1/4 cup each.
Bake in 350 degree F oven 25 minutes or until toothpick inserted into centers comes out clean. Let cupcakes cool in pan on wire rack for 5 minutes. Remove cupcakes from pan to wire rack; let cool completely.
Beat together butter, sugar, walnut extract and milk in medium-size bowl until smooth. Spread 2 tablespoons over each cupcake. Decorate tops with chopped walnuts. Cupcakes can be refrigerated for up to 1 week.