Sweet Potato Coffee Cake - cooking recipe

Ingredients

2/3 cup nonfat yogurt (or applesauce, originally melted butter)
3/4 cup granulated sugar
2 large eggs
2 teaspoons vanilla (original called for 1 tsp)
1 cup nonfat sour cream
3/4 cup cooked mashed sweet potatoes (I increase this to 1 C and increase the flour by about 2 T. Also have stirred in 1/2 C small chunks )
1 cup all-purpose flour
1/2 cup quick-cooking oats
1/2 cup whole wheat flour
1 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon salt
Topping
1 cup chopped pecans
1/2 cup light brown sugar, firmly packed
1/2 cup all-purpose flour (I add 1/4 C oats and decrease flour to 1/4 C)
1 tablespoon butter (original calls for 3 T)
2 teaspoons vanilla

Preparation

Heat oven to 325\u00b0.
Grease a 9 to 10-inch springform pan .
In mixing bowl, combine butter, sugar, eggs, and vanilla; add sour cream and mashed sweet potatoes.
In large mixing bowl, combine flour, baking powder, baking soda and salt. Stir first mixture into the flour mixture, stirring just until blended (if using additional sweet potato chunks add now).
Spread batter in prepared pan. Combine topping ingredients until crumbly and sprinkle over the batter.
Bake coffee cake for about 1 hour to 1 hour and 10 minutes, or until a wooden toothpick inserted near center comes out clean (I baked at 350 for 45 minutes and it was perfect). Let cool, loosen edges, and remove sides of pan.