Rhubarb Cardamom Crumble Muffins

Preheat oven to 400 degrees F. Coat a 12-cup muffin pan with cooking spray.

To prepare topping: Combine 1/4 cup flour, 2 tablespoons each brown sugar and butter and 1/2 teaspoon cinnamon in a small bowl.

To prepare muffins: Whisk flour, baking powder, cardamom to taste, cinnamon, baking soda and salt in a medium bowl. Whisk brown sugar and melted butter in a large bowl. Add buttermilk, egg and vanilla and whisk to combine. Add the dry ingredients to the wet ingredients and stir just until combined. Fold in rhubarb. Divide the batter among the prepared muffin cups. Sprinkle with the topping.

Bake the muffins until golden brown and a toothpick inserted in the center comes out clean, 18 to 20 minutes. Let cool in the pan for 10 minutes, then transfer to a wire rack and cool at least 5 minutes more before serving.