Sour Cream Blueberry Coffee Cake

Another of Anne's delish recipes.

1 cup butter
2 cups sugar
2 eggs
1 cup sour cream
1/2 t vanilla
2 cups cake flour (which I never have on hand and regular flour always turns out just fine)
1 t baking powder
1/2 cup blueberries

filling:
1/2 cup packed brown sugar
1 t cinnamon
1/2 cup chopped nuts
mix until combined

cream butter and sugar, add eggs. fold in sour cream and vanilla. sift together dry ingredients, add to wet mixture. fold in blueberries. pour 1/3 batter into greased bundt pan. sprinkle with 1/2 the filling. pour 1/3 batter over top, sprinkle remaining filling. gently swirl cake with a spatula. bake at 350 for one hour. cool and invert onto a serving platter. dust with powdered sugar. serves 12-16

*a note as of 4/20/10. This is Anne. Made this again recently, and this time I actually had cake flour on hand as well as fresh blueberries and its the best this cake has ever tasted. So if you want to take the extra effort, its well worth it to use those 2 ingredients. It takes it from good to extraordinary!