Onion Soup with Cheese Toasts

In a Dutch oven or other heavy 5-quart pot, heat butter and oil over medium. Add onions and garlic; season with salt and pepper. Cover and cook, stirring occasionally, until onions have softened, 12 to 15 minutes.

Uncover and continue to cook, stirring occasionally, until onions are dark golden brown, 25 to 30 minutes more. (If bottom of pot gets too dry, add about 1/4 cup water, and scrape up browned bits with a wooden spoon.)

Add port, and cook until syrupy, 2 to 3 minutes. Stir in broths and 2 cups water; season with salt and pepper, and bring to a simmer. Serve with Cheese Toasts.

To make Cheese Toasts:
Heat broiler, with rack set 4 inches from heat. Place 8 1/2-in-thick slices of baguette on a broilerproof baking sheet. Dividing evenly, sprinkle with 1 cup coarsely grated Gruyere cheese. Broil until cheese is golden, 2 to 4 minutes.