Preheat the oven to 350 F. Lightly grease an 8×8” square baker. Place the apples evenly in the baker and set aside.
In a medium mixing bowl, use an electric mixer to beat together the butter and sugar until smooth. Add the buttermilk, flour, baking soda, baking powder, salt, and vanilla. Beat again until smooth. The batter will be pretty stiff. Light spray a large spoon with cooking spray and spoon the batter in clumps over the apples.
Pour the maple syrup over the batter, then sprinkle the walnuts all over. Bake for 55 to 60 minutes; cover with aluminum foil, shiny side up, after 30 minutes of cooking. Remove the cobbler from the oven and let it cool 10 to 20 minutes before serving. I recommend serving warm with vanilla ice cream. Yum!
