Rhubarb-Sour Cream Snack Cake with Walnut Streusel

Preheat oven to 375 degrees F.

Combine rhubarb and 2 tablespoons flour in a medium bowl; toss well to coat.

Place brown sugar and butter in a large bowl; beat with a mixer at medium speed until light and fluffy. Add eggs, 1 at a time, beating well after each addition. Add sour cream, rind, and vanilla; beat until well combined.

Lightly spoon all-purpose flour and whole wheat flour into bowl. Add baking soda, cinnamon and salt, stirring with a whisk. Gradually add flour mixture to butter mixture, beating at low speed just until combined. Fold in rhubarb mixture. Spread batter into a 9 inch square baking pan coated with cooking spray.

To prepare streusel, combine sugar and cinnamon in small bowl. Cut in butter until mixture is crumbly; stir in nuts. Sprinkle streusel evenly over batter.

Bake at 375 for 50 minutes or until a wooden pick comes out clean.