Peel potatoes and sweet potatoes and then finely slice them approximately 2mm thick (using a mandolin if you have one).
Combine garlic, vegetable stock and cream, in a large capacity bowl or jug.
In a large, deep baking dish, spread half of the potatoes and sweet potatoes in even layers, pouring half of the cream mixture throughout the layering.
Sprinkle half of the cheese and then continue layering the rest of the potato and sweet potatoes, along with the rest of the cream mixture.
Sprinkle the remaining cheese over the top of the dish.
Cover with aluminium foil and cook for 1 1/4 hours.
Remove aluminium foil and cook for a further 15-20 minutes, until golden brown.
Notes
Make sure you give this potato bake the time in the oven it needs, so the potatoes are perfectly tender and flavoursome.