Source: Jean Kressy, Cooking Light
1 cup all-purpose flour
1-1/4 teaspoons baking powder
1/8 teaspoon salt
5 tablespoons unsalted butter, softened
1-1/3 cups granulated sugar, divided
1 teaspoon vanilla extract
1/4 teaspoon ground cinnamon
1 large egg
1/2 cup 1% low-fat milk
4 cups (1-inch-thick) slices rhubarb (about 1 pound)
1 teaspoon powdered sugar
Preheat oven to 350°.
Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, baking powder, and salt, stirring well with a whisk. Place butter in a large bowl, and beat with a mixer at medium speed until smooth. Add 2/3 cup granulated sugar; beat until well blended. Add vanilla, cinnamon, and egg, beating well. Beating at low speed, add flour mixture and milk alternately to sugar mixture, beginning and ending with flour mixture; beat just until smooth.
Combine rhubarb and remaining 2/3 cup granulated sugar in an 8-inch square baking dish coated with cooking spray. Spoon batter over rhubarb mixture. Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean. Sprinkle with powdered sugar.