Step 1

Preheat oven to 180C. Brush a 12-hole muffin tin with oil. Peel potatoes and sweet potatoes, and finely slice into very thin rounds. Season well with salt and pepper. Layer into the holes of the muffin tin, alternating a few slices of each type of potato.

Step 2

In a small saucepan, heat cream and milk with the herbs and garlic until just simmering. Spoon over potatoes to fill almost to the top. Sprinkle with gruyere cheese. Bake for 30 minutes until potatoes are tender and golden.

Step 3

Allow to cool slightly, then use a small spatula or spoon to lift each potato stack to a serving plate.