Put the potatoes into a saucepan, cover with water, bring to a boil and cook for 10-15 minutes, or until they’re fork-tender. Meanwhile, preheat the oven to 425F.
Drain the potatoes well, spread them out on a parchment-lined rimmed baking sheet (don’t crowd the pan too much—you want to give them room to brown) and crush each one flat with a fork. If you like, stir a garlic clove into your melted butter, oil or other fat before drizzling it over the potatoes. Sprinkle with herbs and/or spices, or just salt and pepper.
Roast for 20-30 minutes, or until crisp and golden on the edges. If you like, pull the pan out, grate Parmesan generously overtop and return to the oven for five more minutes. Serves about 4 per pound of potatoes.