Peel the potatoes and depending on their size half, quarter or (if on a small side) leave whole. Try and keep them similar size for even cooking.
Put peeled potatoes in a saucepan and cover them with cold water, season with some salt and put the pan onto boil. Feel free to cover the pan with a lid at this point.
Pour oil into a large roasting tin, place it in the oven and preheat to 180C fan/350F/Gas Mark 5.
Once water has come to rolling boil, turn the heat down slightly so that it retains steady boil and from that point cook the potatoes (uncovered) for 2-3 minutes. Once the time is up drain the potatoes in a colander.
Shake the colander up and down, back and forth few times to fluff up the potatoes a bit. They should be firm enough to retain their shape but looking a bit fluffy on the outside.
Put the potatoes back into the saucepan you used to cook them in and sprinkle over the polenta and nutritional yeast (if using).
Shake the pan vigorously for a bit to evenly coat the potatoes in polenta, nutritional yeast mix.
Take roasting pan out of the hot oven (take care not to burn yourself) and gently put the potatoes into the pan (I like to use kitchen tongs for that) and ensure they are nicely coated in oil.
Add few sprigs of fresh rosemary and/or thyme to the roasting tin and few unpeeled cloves of garlic. Season with salt and pepper and put back into the oven.
Roast the potatoes for approximately 45-50 minutes, turning them twice.