Cook: 4–5 hours on LOW or 2–3 hours on HIGH, plus time for the tortellini
Best size: 6-quart or larger crockpot
1 teaspoon olive oil
1 medium white or yellow onion, diced
1 tablespoon minced garlic (3 cloves)
5 tablespoons tomato paste
8 cups chicken stock
1 (28-ounce) can diced tomatoes
1 tablespoon Italian seasoning
1½ teaspoons kosher salt
1½ teaspoons black pepper
1½ teaspoons garlic powder
1½ teaspoons onion powder
¼ teaspoon crushed red pepper flakes
1 (14- to 16-ounce) package frozen Italian meatballs 1 (18- to 20-ounce)
package frozen cheese tortellini
10 ounces baby spinach
1 cup grated Parmesan cheese, plus more for garnish
Step 1. Build your soup base
Put these directly into the crockpot:
Olive oil, onion, garlic, and tomato paste
Chicken stock and diced tomatoes (including juice)
All the seasonings
Frozen Italian meatballs
Stir everything together until the tomato paste is reasonably well distributed.
My one optional improvement: If you feel like it, sauté the onion and garlic with the tomato paste first, just as your original recipe directs. You'll get a richer flavor. But you can skip that entirely when you want an easy day.
Step 2. Let the crockpot do the work
Cook covered on:
LOW: 4–5 hours
HIGH: 2–3 hours
The meatballs should be heated all the way through, with the center reaching 165°F.
Step 3. Add the frozen tortellini near the end
About 30 minutes before you're ready to eat, turn the crockpot to HIGH and stir in the frozen tortellini.
Cook for approximately 20–30 minutes, checking after 15–20 minutes. They should be tender but not falling apart.
Don't add them at the beginning! Tortellini left in a crockpot for four hours will become little pasta pillows of despair.
Step 4. Add the spinach and cheese
When the tortellini is nearly tender:
Stir in the baby spinach.
Cover and cook another 5–10 minutes, until wilted.
Turn off the heat, then gradually stir in the Parmesan.
Ladle into bowls and add more Parmesan if you'd like.
A couple of things I'd change
I'd start with 7 cups of chicken stock instead of 8. Crockpots don't evaporate liquid the way stovetop cooking does. You can always add that last cup if the soup seems too thick.
I'd also start with just 1 teaspoon of salt. The stock, meatballs, and Parmesan can contribute quite a bit of salt. Taste before serving and add more if needed.
One other consideration: this recipe makes a generous batch. With 8 cups of stock, 28 ounces of tomatoes, meatballs, tortellini, and 10 ounces of spinach, a 6-quart crockpot may be rather full. An 8-quart would be more comfortable.
And here's my favorite practical trick: If you're planning to eat this soup over several days, cook the tortellini separately and add it to each bowl. Otherwise, it will keep absorbing broth in the refrigerator, and by the following day you'll have something closer to meatball-and-tortellini stew.
Which, admittedly, might be rather delicious too.