Ingredients
4 tablespoons unsalted butter, room temperature
1 cup packed light-brown sugar
1 large egg
3/4 cup low-fat buttermilk
2 cups all-purpose flour (spooned and leveled)
1 1/2 teaspoons baking powder
1 teaspoon baking soda
1/2 teaspoon salt
6 to 8 ounces rhubarb, ends trimmed, cut into 1/2-inch chunks (1 1/2 cups)
Nonstick cooking spray
1 tablespoon granulated sugar
Preparation
Preheat oven to 375 degrees. With an electric mixer, beat together butter and brown sugar in a large bowl until smooth. Beat in egg; add buttermilk, and beat to combine.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Add to butter mixture; beat until smooth. Fold in rhubarb.
Coat a standard (12-cup) muffin tin with cooking spray. Spoon mixture into prepared tin, dividing evenly among cups. Sprinkle with granulated sugar.
Bake until a toothpick inserted in center of a muffin comes out clean, about 25 minutes. Cool in pan on a wire rack 15 minutes. Turn out muffins onto rack; cool completely.
