Blueberry Muffins
["4 Tbsp. butter", "2/3 c. sugar", "2/3 c. milk", "1 egg yolk", "1 3/4 c. flour", "4 tsp. baking powder", "1/2 tsp. salt", "1 c. blueberries"]
["Cream butter and sugar.", "Add egg yolk.", "Mix flour, salt and baking powder.", "Alternating, add dry ingredients with milk and butter mixture.", "Beat egg white until fluffy and fold into batter. Add blueberries."]
["butter", "sugar", "milk", "egg yolk", "flour", "baking powder", "salt", "blueberries"]