3 cup all-purpose flour, stir before measuring
1 tsp. baking powder
1 tsp. baking soda
1/2 tsp. salt
3 tsp. ground cinnamon
1/2 tsp. ground nutmeg
3/4 cup (1 1/2 sticks) butter
1 cup sugar
2 eggs
2 tsp. vanilla extract
1/2 cup sour cream
1/2 cup milk

Preheat oven to 350°F.

Prepare Streusel (See below). On wax paper, thoroughly stir together flour, baking powder, soda, salt, cinnamon and nutmeg.

In a large bowl, cream butter and sugar; beat in eggs, one at a time, along with the vanilla. Stir in flour mixture in 4 additions, alternately with sour cream and milk, and beating just until smooth each time.

Turn half the batter into a greased 9-inch angel food cake pan; spread half the Streusel over the batter; add remaining batter and top with remaining Streusel.

Bake preheated 350°F oven until a cake tester inserted in center comes out clean - about 45 minutes.

Stand cake in pan on a wire rack for 10 minutes; with a small spatula loosen cake around edges and tube; turn out on wire rack. Using another rack, turn right side up.

Allow to cool completely. Store in an air-tight container or wrap well and refrigerate.

Serve at room temperature.

Streusel:

1/4 cup (1/2 stick) butter
2 tsp. ground cinnamon
1/2 tsp. ground nutmeg
1/2 cup firmly packed dark brown sugar
1 cup chopped (medium-fine) walnuts

In a small saucepan or skillet over low heat, melt the butter; stir in cinnamon, nutmeg and brown sugar. Remove from heat and stir in walnuts.