Whisk flour, cornstarch,baking powder, salt and all spices in a bowl

Beat butter and light brown sugar until light and fluffy, 2 minutes. Add the eggs one at a time beating after each egg, add vanilla. Then alternate flour mixture with buttermilk and beat until just smooth

Divide batter evenly into prepared pans, smooth tops and bake 15 to 23 minutes until a toothpick comes out just clean. Cool on rak 10 minutes then remove from pans and cool completely

Place one layer of cake, bottom up on serving plate

Place second layer of cake on frosted first level bottom side up and frost it

Place third last layer, top side up and frost entire cake

Garnish cake with the cashews, almonds and pistachios. Chill cake at least 1 hour for easier cutting