Maple Walnut Cake
["2 2/3 c. cake flour", "3/4 tsp. baking soda", "1/2 tsp. salt", "1/4 tsp. baking powder", "3/4 c. buttermilk", "1/2 c. pure maple syrup", "14 oz. unsalted butter (room temperature)", "1 c. sugar", "1 1/4 tsp. maple extract", "1 tsp. vanilla extract", "3 eggs", "1 c. finely chopped walnuts", "3 c. confectioners sugar", "1 c. Marshmallow Creme", "walnut halves for decoration"]
["Preheat oven to 350\u00b0.", "Butter and flour two 9-inch cake pans. Combine flour, soda, salt and baking powder.", "Combine buttermilk and maple syrup.", "With an electric mixer set at medium-low speed, beat 6 ounces butter (12 tablespoons) and the granulated sugar until light and fluffy, about 5 minutes.", "Beat in 1 teaspoon maple extract and the vanilla.", "Beat in eggs, one at a time, beating well after each addition.", "Reduce speed and beat in flour mixture in 3 parts, alternating with buttermilk mixture.", "Stir in chopped walnuts.", "Pour into prepared pans and bake about 25 minutes.", "Cool 10 minutes in pans.", "Remove from pans and cool completely on wire rack."]
["cake flour", "baking soda", "salt", "baking powder", "buttermilk", "maple syrup", "unsalted butter", "sugar", "maple", "vanilla extract", "eggs", "walnuts", "confectioners sugar", "Marshmallow Creme", "walnut halves"]