Name: Sweet Onion Potato Gratin
Prep time: 5 min
Cook time: 25 min
Yield: 4
Cuisine: French
Ingredients: 30g butter; 1 large or 2 medium sweet onions, thinly sliced; Salt and freshly ground black pepper; 1/2 tsp ground thyme; 1 bay leaf, fresh or dried; 910g baby gold or fingerling potatoes; 125 to 160ml double cream; 50g grated Parmigiano Reggiano; 225g Gruyere or Swiss cheese, shredded