Preheat oven to 350 degrees F. Line two 8x8x2-inch baking pans with parchment paper. Grease and flour the pans; set aside.
In mixing bowl whisk buttermilk, oil, brown sugar, eggs, baking powder, cinnamon, baking soda, salt and vanilla until combined. Whisk in flour; stir in apple. Divide evenly between prepared pans.
Bake 40 minutes or until wooden toothpick inserted near center comes out clean. Cool in pans on wire rack 10 minutes. Invert cake layers from pans onto racks; remove parchment paper. Cool completely on racks.
Prepare Fruit Topper. Place one cake layer, flat side up, on serving platter. Spoon on about two-thirds of topper. Top with second cake layer and remaining mixture. Serve immediately. Makes 10 servings.
In skillet melt butter over medium heat. Add apples or pears; add granulated sugar. Cook, stirring occasionally, just until fruit begins to soften, about 8 minutes. Remove from heat.