This is truly the BEST 15-Bean Soup recipe I've ever tasted! This soup starts with a package of dried assorted beans (NO overnight soaking required) that get cooked in the slow cooker or pressure cooker until perfectly tender.
15-BEAN SOUP (slow cooker): Add everything listed under "beans" to a slow cooker. Do not add the seasoning packet, and be sure to only add two cups of beans. Season to taste, I add 1 tsp salt & 1/2 tsp pepper. Cook 8 hours on low or high for 4 hours.
15-BEAN SOUP (pressure cooker): Add everything listed under "beans" to a pressure cooker (AKA Instant Pot). Do not add the seasoning packet, and be sure to only add two cups of beans. Season to taste, I add 1 tsp salt & 1/2 tsp pepper. Seal the instant pot, turn the valve to seal, and cook on manual mode for 45 minutes. (Keep in mind that it takes about 15-20 minutes to get up to pressure.) Once finished, allow for a natural release for 25 minutes (I recommend setting a timer so you don't forget!) before releasing the rest of the pressure manually.
15-BEAN SOUP (stove top): Soak beans overnight (or 8 hours). Drain the beans and discard the liquid. Then add soaked beans and 8 cups stock or broth to a large pot. Bring to a boil then reduce heat and simmer (uncovered) for 2-1/2 hours. After beans are tender, pour in the vegetable cream mixture (Instruction #4-6) and simmer until thickened and creamy.
VEGGIES: Add olive oil to a large pot over medium-high heat. Add onion, celery, and carrots; season to taste (I add 1/2 tsp each of salt & pepper). Sauté, stirring occasionally, until very tender (~10-12 minutes). Add in garlic and sauté 1 minute. Add in 2 cups of milk and stir.
THICKEN: In a separate bowl, add the remaining 1/2 cup milk and 1/3 cup cornstarch. Whisk with a fork until completely smooth. While stirring constantly, pour the mixture into the pot. Stir until the sauce is very thick. Once it has thickened, scrape all of it with a spatula into the pressure cooker or slow cooker. Mix well until the soup is smooth. Slow cook with the lid on for 20 minutes on high or sauté in the Instant Pot for about 5 minutes--until heated through and thickened to your liking.
FINISHINGTOUCHES: Taste and adjust seasonings; I typically add another 1/2-3/4 tsp salt & 1/4 tsp pepper. If you feel like it needs an extra boost of flavor, add in some chicken bouillon powder to taste (1-2 tsp.) For some acidity, add in a squeeze of lemon juice or a swish of red wine vinegar. The flavors should sing!
SERVE: Serve bowls garnished with a sprinkle of parsley and some Parmesan cheese if desired. Serve some crusty warmed bread on the side if desired.
Video
Notes
Note 1: Preparing the bean mix: We only want 2 cups, not the whole bag! Discard the seasoning packet (or use it in a different recipe). Rinse the beans in a strainer and pick through them, discarding any shriveled beans, debris or rocks.Note 2: Stock: The better the flavor of the stock, the better this soup will taste! We like Swanson's Chicken Stock best, but if you want a vegetarian soup use their vegetable stock.Note 3: Milk: We like whole milk best -- it will deliver the creamiest, most flavorful soup. That said, 1% and 2% will work. I don't recommend skim milk or milk alternatives.