Smoky French Onion Soup

Prepare a wood-fired oven or cooker for cooking with indirect heat.

Heat the olive oil over medium heat in a 4-quart Dutch oven or clay pot, then add the butter to melt. Add the onions and cook over indirect heat, stirring frequently, until they soften and just begin to brown, about 40 minutes.

Add 1/2 cup of the stock and move the pot to high heat. Stir to scrape up the browned bits from the bottom of the pot and cook until the stock has completely evaporated. Add the Madeira, Worcestershire sauce, and another 1/2 cup of the stock. Add the nutmeg and stir. Repeat, adding 1/2 cup stock and cooking until evaporated, 2 more times.