Preheat the oven to 400F. In a large bowl or the bowl of a food processor, combine the flour, oats, sugar, baking powder and salt. Stir or pulse to blend. Add the butter and blend with a fork or pastry cutter, or pulse again until the mixture is combined, with some pieces of fat the size of a pea.

If you used a food processor, pour the mixture into a bowl. Add the milk and stir until the dough starts to come together; add the chocolate and stir just until combined. Pat into a 1-inch circle on a parchment-lined sheet and cut into wedges with a sharp knife.

Pull them apart so that they're about an inch apart on the sheet, and if you like, brush with milk or cream and sprinkle with sugar. Bake for 15-20 minutes, until golden.