Your family will love this fun departure from the Italian classic—and you’ll love its ease and simplicity. Want to make it in an Instant Pot? Get the recipe here.
Cook beef in a large nonstick skillet over medium-high, stirring to crumble, until browned, about 5 minutes. Transfer to a 5- to 6-quart slow cooker. Add mushrooms, onion, bell pepper, and garlic, and stir to combine. Add stock, tomatoes, tomato paste, oregano, salt, and black pepper; stir to combine. Cover and cook on low 6 hours.
Stir lasagna noodles into soup, making sure to submerge all noodles in liquid. Cover and cook on low until noodles are al dente, about 30 minutes. Stir in half-and half.
Divide soup evenly among 8 bowls. Top evenly with mozzarella and basil.