Preheat the oven to 220C/425F/gas mark 7. Heat the fat in a small, ovenproof, heavy-based frying pan (about 20cm diameter) until it sizzles. Add the bacon and cook until crisp.
Meanwhile, mix the cornmeal, baking powder, salt and sugar in a large bowl and whisk the egg and buttermilk in a jug. Lift the bacon out of the pan with a slotted spoon and set aside, keeping the pan on the heat.
Pour the egg mixture into the cornmeal mix and stir, then fold through the bacon and peel, followed by the bacon drippings from the pan.
Tip the batter into the hot pan and bake for about 25 minutes, until golden on top. Let it sit for a few minutes before turning it out. Serve cut into wedges, with plenty of butter.