Cheese-Topped Baked Reuben Soup

Heat butter and oil in a large, heavy soup pot over medium-high flame. Stir in onions and a few pinches each of salt and pepper (if you’re using canned broth, go easy on the salt). Let onions cook, stirring often, until limp and pale golden, about 15 minutes. Reduce heat to medium, add caraway seeds, and continue to cook until onions are golden brown to medium brown, stirring them often, adjusting the heat so they don’t burn, and scraping up the darker caramelized bits at the bottom of the pan—this will take another 10 to 15 minutes.

Stir in broth, beer, sauerkraut, corned beef and pickles. Simmer slowly 20 to 30 minutes. If time permits, turn off heat and let soup stand at room temperature 1 hour or longer, to develop more flavor.

While soup is cooking (or resting), heat oven to 350 degrees. Arrange rye bread slices in a single layer on a baking sheet and toast in the oven for 10 to 15 minutes, depending on how dark you like them, flipping halfway.

To finish and serve soup:

Heat oven to 450 degrees. Bring soup back to simmer. Taste for seasoning and add additional salt and pepper as needed. (Salt may not be necessary here because of other salty ingredients). Place ovenproof cups or bowls on a rimmed baking sheet. Ladle soup into them and cover with toasted rye bread and a generous mound of shredded cheese. Bake until cheese is bubbly, brown-tipped and crusty around the edges. Serve each bowl on a plate—and alert your diners about the hot bowls.