Blackberry Muffins

Preheat oven to 375°F. Stir together flour, baking powder, and salt in a bowl; set aside. Beat butter and 1 cup of the sugar in a stand mixer fitted with a paddle attachment on medium speed until smooth and fluffy, 2 to 3 minutes. Reduce mixer speed to low; beat in eggs, buttermilk, and lemon zest until combined, about 30 seconds. Add flour mixture, beating until combined. Fold in blackberries.

Spoon mixture into a 12-cup muffin tray coated with cooking spray, filling each cup about two-thirds full. Sprinkle evenly with remaining 2 tablespoons sugar. Bake in preheated oven until a wooden pick inserted in centers of muffins comes out clean, 20 to 25 minutes, rotating tray 180 degrees halfway through bake time. Let cool in tray 5 minutes. Transfer to a wire rack, and let cool completely, about 20 minutes.