Make beef and cabbage soup by cooking 1 pound of ground beef and 1/2 onion in 2 tablespoons of oil at medium-high heat and placing the beef, 5 cups of chopped cabbage, 2 cans of red kidney beans, 2 cups of water and 24 ounces of tomato sauce in a slow cooker. Season everything with 4 beef bouillon cubes, 1 1/2 teaspoons of cumin, and 1 teaspoon each of salt and pepper. Cook the soup on high for four hours.
To make corned beef and cabbage soup, blend 1 medium onion, 3 stalks of celery and 3 medium carrots in a food processor, and cook the vegetables along with 1/4 teaspoon of ground allspice in 3 tablespoons of unsalted butter at medium-high heat for five minutes. Add 1 pound of finely chopped plum tomatoes, 3 cups of low-sodium beef broth, 4 cups of chopped green cabbage, 1/2 pound of chopped Yukon gold potatoes and 3/4 cup of quick-cooking barley into the pot, and mix in 4 cups of water.
Cook the mixture covered until it boils, and then simmer the soup uncovered on medium-low heat for 20 minutes. Add 1/4 pound of corned beef strips and kosher salt and pepper to taste, and serve.