California Coffee Cake

Ingredients
Filling:    
1/2 cup packed brown sugar
1/2 cup chopped walnuts  
1 tsp. cinnamon  1 TBS. melted butter  
1 TBS. flour    
Batter:    
1 cup sugar   1/2 cup butter 
1 1/2 cups flour   2 eggs - separated  
2 tsp. baking powder   1 tsp. salt  
1/2 cup milk  grated peel of 1 lemon and 1 orange  


Directions

Serves 8