In a large skillet, brown onion and veggie crumbles in olive oil over medium heat until onions are translucent and crumbles are warmed through. Note: If you're using your Instant Pot for slow cooking, you won't need to dirty and extra skillet. Just use the saute setting!
Now, transfer onions and crumbles to a slow cooker. Then add all remaining ingredients.
Next, cover and cook on low for 6 to 8 hours.
Dinner's ready! Serve your stuffed green pepper soup with a sprinkle of vegan parmesan and a slice of warm, crusty bread. Enjoy!