American French onion soup

Peel and halve the onions; cut across at the widest point, then four or five cuts the other way into large rectangles rather than thin strips.

Melt butter in a large oven-safe skillet over medium heat; add the onions with a big pinch of salt and stir to coat.

Brown in a 425F oven, stirring every 15 to 20 minutes, about an hour, until soft, sweet and well caramelised.

Finish on the stove over medium heat until a dark brown fond forms on the bottom.

Deglaze with a little splash of sherry and an even smaller splash of sherry vinegar, scraping the bottom and sides with a wooden spoon until the liquid has nearly evaporated; turn off the heat.

Transfer to a soup pot with a few sprigs of thyme and the beef and chicken broth; bring to a boil on high, skimming foam and fat.

Simmer on low at least an hour, longer is better, topping up with stock or water to keep the level; season with salt and black pepper.

Paint French bread generously with melted butter and crisp under a broiler or in a hot oven without burning.

Fill heatproof bowls, top with a crouton, cover it completely with half cheddar and half Monterey Jack and a little cayenne.

Broil about 6 inches from the heat for 5 or 6 minutes.