• 1 c. chopped walnuts, optional
In a large bowl, whisk together flour, baking powder, sugar, salt and baking soda. In another bowl, whisk together buttermilk, eggs and 3 tablespoons melted butter. Add buttermilk mixture to flour mixture and stir until combined. Cover and refrigerate at least 15 minutes but preferably overnight (if batter sits overnight, stir it well before pouring; you may need to thin it with a little more buttermilk). Berries may be stirred into batter at this point, if desired.
Heat a griddle or large cast-iron skillet over moderate heat until hot enough to make drops of water scatter over surface. Brush grill or skillet with additional melted butter.
Working in batches, pour batter onto griddle or skillet to form pancakes about 6 inches in diameter. Sprinkle pancakes with walnuts at this point, if desired.
When most bubbles on top of pancake begin to pop, flip pancakes and cook about 1 minute more. Transfer cooked pancakes to a warm platter. Serve with butter and maple syrup.