In a bowl, whisk together the dry ingredients: flour, sugar, baking powder, baking soda, and salt.
In another bowl, whisk together the wet ingredients: buttermilk, melted butter, and egg.
Whisk flour mixture into buttermilk mixture until moistened, with small to medium lumps remaining.
In a large cast-iron, nonstick skillet or on a griddle, cook bacon over medium-high until fat is rendered and bacon is browned on one side, about 5-6 minutes. Flip and cook until golden and crisp on the underside, about 1-3 minutes more.
Set bacon aside on paper towel-lined plate. Pour off all but 1 tsp fat from skillet, saving excess bacon fat in a container.
Heat skillet over medium. Pour 1/4 cup of batter into skillet and top each with a bacon slice.
Cook until some bubbles appear on top of pancakes and a few have burst, about 2 minutes. With a spatula, carefully flip the pancakes and cook until browned on the underside, about 2 minutes more.
Transfer to a platter, bacon side up, and loosely tent with foil.
Keep pancakes warm in the oven and repeat with remaining batter, adding more bacon fat if needed. Serve with pure maple syrup.