Blueberry Muffins
["1 Tbsp. butter, softened, plus 4 Tbsp. butter, melted and cooled", "1 c. blueberries", "2 3/4 c. flour", "3/4 c. sugar", "4 tsp. baking powder", "1/2 tsp. salt", "1 c. milk", "1 egg, lightly beaten"]
["Preheat the oven to 400\u00b0.", "With a pastry brush, spread the softened butter over the inside surfaces of a medium-sized 12-cup muffin tin (each cup should be about 2-inches across the top)."]
["butter", "blueberries", "flour", "sugar", "baking powder", "salt", "milk", "egg"]