For the potato gratin, peel the potatoes and cut into slices about 1/2 cm thick. Brush a baking dish with olive oil and layer in the sliced potatoes.
Mix whipping cream, sour cream, Parmesan cheese and squeezed garlic and season with salt and pepper. Pour the mixture over the potatoes and bake the potato gratin in the preheated oven at approx. 150° C for 50 – 60 minutes.