Peel and wash the potatoes and kohlrabi, cut into fine slices with a mandolin.
Peel the shallot and garlic and chop finely. Crush with a mortar or mix finely with thyme leaves to an herb paste. Warm the butter with the oil and mix in the herb paste.
Use greased ramequins, muffin moulds or punch out rounds of the potato and kohlrabi. Just make sure the potatoes fit into your mould.
Place the potatoes and kohlrabi alternately in the moulds.
Brush each layer with the herb butter and season with salt and pepper. Build up until all the ingredients are used up or the moulds are filled. Sprinkle some grated cheese between each layer of potato.
Cover with aluminium foil and place in the middle of the oven for 30 to 35 minutes. Remove the foil and continue baking for 15 to 20 minutes until the potatoes and kohlrabi are cooked and golden brown.