Apple Cinnamon Muffins
["1 1/2 c. all-purpose flour", "1/3 c. granulated sugar", "2 tsp. baking powder", "1 tsp. ground cinnamon, divided", "1/2 tsp. salt", "1 egg", "1/2 c. milk", "1 c. finely chopped apple (1 large), peeled and cored", "4 Tbsp. (1/2 stick) butter, melted", "1/3 c. chopped nuts (any kind)", "1/4 c. firmly packed brown sugar"]
["Preheat oven to 375\u00b0.", "In a large bowl, combine flour, granulated sugar, baking powder, 1/2 teaspoon cinnamon and salt. In another bowl, beat egg with milk, then stir in apple and melted butter.", "Add all at once to flour mixture and stir until just moistened.", "Spoon batter into a greased muffin tin(s), filling each cup about 2/3 full."]
["flour", "sugar", "baking powder", "ground cinnamon", "salt", "egg", "milk", "apple", "butter", "nuts", "brown sugar"]