Heat oven to 375°F.
Heat 1 tablespoon butter in large ovenproof skillet over medium heat. Add apple, lemon juice and granulated sugar; cook, stirring, until crisp-tender, 5 minutes.
Meanwhile, stir together flour, light-brown sugar, baking powder, salt and baking soda in large bowl until well mixed. Stir buttermilk and egg in small bowl. Make well in center of dry ingredients. Add buttermilk mixture to well; stir together until well blended.
Add remaining butter to apples in skillet. Heat over medium heat until butter is melted. When it is bubbly, spoon pancake mixture on top, spreading evenly to sides.
Bake in 375°F oven for 25 to 30 minutes or until set and golden on top and wooden pick inserted in center comes out clean. Let stand 5 minutes. Loosen sides with metal spatula. Invert onto serving plate.