1 3/4 c. flour
1 1/2 c. sugar
2/3 c. cocoa
1 1/2 tsp. baking soda
1 tsp. salt
1 1/2 c. sour cream or yogurt
1/2 c. butter, softened
2 eggs
1 tsp. vanilla
1/2 c. chopped nuts
Confectioners' sugar

Heat oven to 350 degrees. Grease and flour 13x9x2 pan.

Prepare crater filling; set aside.

In large mixer bowl stir together flour, sugar, cocoa, baking soda, and salt. Add sour cream or yogurt, butter, eggs, and salt. Add sour cream or yogurt, butter, eggs and vanilla; blend on low speed. Beat on medium speed for 3 minutes, scraping bowl occasionally.

Pour batter into prepared pan. Place 1/2 teaspoon of filling 1 inch apart on top of batter. With fork, streak filling lightly over batter. Sprinkle nuts on top. Bake 35-40 minutes. Cool. Sprinkle with confectioners' sugar.

CRATER FILLING:

3 tbsp. butter
3 tbsp. cocoa
2/3 c. confectioners' sugar
1 tbsp. milk
1/4 tsp. vanilla

Mix butter in saucepan over low heat. Add cocoa, stirring constantly until blended. In small mixer bowl combine confectioners' sugar, milk and vanilla. Add cocoa mixture; beat on high speed 2 minutes.