Rhubarb Coffee Cake
1 cup white flour
1 cup whole wheat pastry flour
1 teaspoon baking powder
½ teaspoon baking soda
½ teaspoon salt
½ teaspoon cinnamon
½ cup butter
½ cup brown sugar
¼ cup white sugar
1 teaspoon vanilla
1 cup buttermilk
2 cups chopped rhubarb
1 cup chopped walnuts (optional)
In a medium bowl, mix together the white and wheat flour, baking powder, baking soda, salt, and cinnamon.
In a large, bowl, cream together the butter, brown sugar, and white sugar. Mix in egg and vanilla.
Add a little of the flour mixture to butter mixture, alternating with a little buttermilk until all is incorporated, then fold in rhubarb. If desired, add up to one cup chopped walnuts—black walnuts are nice if you have them.
Spread batter in a greased 9 x 13 pan.
Optional streusel topping: Mix together ¼ cup brown sugar, ¼ cup flour, ¼ cup butter and 1 teaspoon cinnamon until crumbly. Sprinkle on top of cake batter.
Bake at 350 degrees for about 35–45 minutes until lightly browned and a cake tester comes out clean.