In a large skillet, heat olive oil over medium heat. Add onion and vegan sausage, breaking the sausage up with a spoon. Cook until the sausage is cooked through and the onion starts to turn translucent.
Add garlic and cook for another minute. Remove from the heat.
Add sausage and onion mixture to your slow cooker, along with carrots, dried oregano, dried basil, dried thyme, red pepper flakes, kosher salt, black pepper, vegetable broth, and crushed tomatoes. Stir to combine.
Cook on high for 3 hours or low for 6 hours.
When the time is up, stir in the vegan tortellini and cook on low until tender, about 5 to 7 minutes.
Finally, stir in coconut milk, vegan parmesan cheese, and chopped kale and let cook until warmed through and the kale is bright and tender.
Serve hot garnished with fresh parsley and a side of crusty bread.
Notes
Make Ahead Instructions: If you'd like to make this creamy vegetarian tortellini soup for meal prep, there are a few options.
Cook in advance: This tortellini soup can be cooked in advance and stored in an airtight container in the refrigerator for up to 3 days. To ensure the tortellini does not become too soft and mushy, I'd recommend cooking the soup as is without the tortellini(cook and store it separately!), then stir the cooked tortellini into the soup just before reheating.
Prep the soup ingredients in advance: You can also place the browned sausage, onion, garlic, carrots, dried spices, and crushed tomatoes in a large bag or airtight container and refrigerate until ready to cook. Then, when ready to cook, dump the ingredients in the slow cooker, add the vegetable broth and resume the cooking instructions. This is a great option if you'd like to cook fresh but don't have time to prep in the mornings!
Freezer Instructions: Similar to my make ahead instructions (see above!), I'd recommend either freezing the cooked base of the soup as is without the tortellini or freezing the ingredients in a freezer-safe container or bag together before slow cooking. Then, when ready to cook, dump the ingredients into the slow cooker straight from frozen, add the broth and resume the cooking instructions as recommended. Freezing the tortellini in the cooked soup is not recommended - it will overcook and become soft and mushy.