Despite being relatively low in fat, this soup is incredibly rich and hearty – you don't need to add much to turn it into a meal! Serve it simply with a piece of crust baguette or, my favorite, pretzel goldfish. A side of steamed broccoli rabe keeps things tasting light and fresh (and it's delicious dunked into the cheesy broth.) Don't be tempted to dump the cheese in all at once; if it isn't added slowly it will bind together into a huge congealed mass instead of melting into the soup. Also, steer clear of pre-shredded cheese. It's coated with starch and won't melt right at all. I like Cabot 50% Reduced Fat Sharp Cheddar.
Fill a pot of water with a steamer insert and bring to a boil. Add the cauliflower to the insert, cover, and steam for 10-15 minutes, or until very soft.
While the cauliflower steams, heat the olive oil in a medium-sized (about 5 quart), heavy-bottomed pot. When the oil is hot, add the onion, celery, jalapeño, and garlic. Cook, stirring occasionally, for 5 minutes, or until soft. Sprinkle with the flour and paprika, stir, and cook for 1 minute. Add half the beer. Simmer for 5 minutes, or until the beer is reduced by about half. Add 2-1/2 cups of the chicken stock and simmer over low heat for 10 minutes.
Little by little, add in the shredded cheese, letting it melt completely between additions. Add the remaining beer.
Add the remaining 1/2 cup chicken stock and the steamed cauliflower to a food processor or blender and process until very smooth. Stir into the soup.