Preheat the oven to 180°c (160° fan/ Gas 4/ 350F) and lightly butter a 20 x 30cm baking dish.
Peel and finely slice the potatoes with a sharp knife (or use a food processor with slicer attachment) to about 4mm thickness.
800 g White Potatoes
Melt the butter in a large pan and cook the onion, garlic, and thyme on a low - medium heat for 8-10 minutes, until soft.
25 g Butter, 1 Onion, 2 Garlic Cloves, 1 tablespoon Fresh Thyme Leaves
Place a layer of sliced potatoes on the bottom of the baking dish, season with salt and black pepper, and then follow with a layer of the onion mixture.
½ teaspoon Salt, ¼ teaspoon Black Pepper
Repeat the layers until all the potato and onion mix has been used up, making sure you finish with a top layer of potatoes (I get three layers of each in my baking dish). Pour over the vegetable stock.
300 ml Vegetable Stock
Sprinkle over the Parmesan and bake in the oven for 1 hour, or until the potatoes are golden and cooked through.
50 g Parmesan