- 3/4 cup old-fashioned rolled oats, divided
- 1 cup all-purpose flour
- 1/4 cup whole wheat flour
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/4 teaspoon kosher salt
- 1/2 cup granulated sugar
- 1/2 cup packed dark brown sugar, divided
- 1/3 cup butter, softened
- 2 large eggs
- 1 teaspoon pure vanilla extract
- 8 ounces sour cream
- 1/2 teaspoon ground cinnamon
- 1 tablespoon chilled butter, cut into small pieces
Preheat oven to 350F degrees. Spread oats in single layer on baking sheet. Bake for 6 minutes or until lightly brown. Coat 9-inch spring-form baking pan with non-stick spray. Set aside.
Reserve 1/4 cup oats and set aside. Place remaining oats in food processor. Process until finely ground. Combine processed oats, flours, baking powder, baking soda, and salt. Stir with whisk.
Place granulated sugar, 1/4 cup brown sugar, and 1/3 cup butter in large bowl. Beat with mixer on medium speed for 3 minutes or until light and fluffy. Add eggs, one at a time. Beat well after each addition. Beat in vanilla. Add flour mixture to sugar mixture alternatively with sour cream. Begin and end with flour mixture. Batter will be slightly lumpy. Spoon batter into prepared pan. Spread evenly.
Combine remaining 1/4 cup oats, brown sugar, and cinnamon in a bowl. Cut in 1 tablespoon butter with pastry blender until well blended. Sprinkle evenly on top of batter.
Bake for 38 minutes or until wooden pick inserted in center comes out clean. Top should be golden and cake should start to pull away from sides of pan. Cool in pan for 10 minute before removing. Yields 10 servings.
