Instructions: In large bowl, beat together egg, yolk, and sugar until well blended; beat in sour cream, oil and vanilla. Stir together flour, baking powder, baking soda, cinnamon and salt; stir into egg mixture.

Topping: In bowl, stir together sugar, flour, cocoa, and cinnamon.

With pastry blender or 2 knives, cut in butter until crumbly; stir in nuts.

Spread half of the batter in an ungreased 8-inch square microwaveable baking dish; sprinkle with half of the topping. Repeat with remaining batter and topping. Shield corners of dish well with foil triangles; place on inverted saucer in oven. Microwave at HIGH for 2 to 4 minutes, rotating dish one; remove foil. Microwave at HIGH for 2 to 4 minutes or until cake tested inserted in center comes out clean; rotating dish once. Let stand on flat surface for 10 minutes before serving warm.

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