Preheat the oven to 200C. Scrub the sweet potatoes well. Cut each one into 5cm (2-inch) thick rounds. Lay flat on a large tray lined with baking paper.

Bake in the oven for 15-20 minutes. Remove them from the oven and set aside.

Mash the butter with the crushed garlic cloves and finely grated Parmesan. Turn each piece of sweet potato over and squash gently with a fork. Top with a little of the garlic butter.

Return to the oven for another 10 minutes until the garlic butter is bubbling and the cheese is melted. Scatter with the parsley and serve.