Prepare the Apple Topping: In a skillet over medium heat, melt the butter. Add the diced apples, brown sugar, cinnamon, and nutmeg. Cook for about 5-7 minutes, stirring occasionally, until the apples have softened and are slightly caramelized. Remove from heat and set aside.
Make the Pancake Batter: In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and ground cinnamon. In another bowl, combine the buttermilk, egg, melted butter, and vanilla extract. Stir until well mixed. Pour the wet ingredients into the dry ingredients and mix until just combined. Be careful not to overmix; a few lumps are okay.
Cook the Pancakes: In the same skillet used for the apples, keep it over medium heat and lightly grease with a bit of butter or oil as needed. Pour a scoop (about 0.25 cup) of pancake batter into the skillet. Cook until bubbles form on the surface, about 2-3 minutes. Gently flip the pancake and cook for another 1-2 minutes, until golden brown. Repeat with remaining batter, adjusting the heat as needed to prevent burning.
Combine and Serve: Layer the warm pancakes on a plate, and top with the caramelized apple mixture. Sprinkle with chopped walnuts or pecans if desired. Drizzle with maple syrup for added sweetness and warmth.
Enjoy: Serve immediately while warm, and savor the cozy flavors of apple and cinnamon!