In a large pot on the stove top, sauté onions and garlic in butter and oil until soft.
Add in quartered mushrooms and continue to sauté until mushroom juices are released.
Stir in diced carrots and cook for a minute more.
Sprinkle over the flour, stir and cook for a couple minutes.
Gradually add about 1 cup of water, stirring to incorporate and smooth the flour roux.
Mix in bouillon, paprika, parsley, thyme and bay leaf.
Add the passata, mushroom soup and water. Stir and bring to a boil.
Add in meatballs and drained potatoes. Return to a boil then reduce heat and simmer for 10 minutes. Season to taste with salt and pepper.
Serve with fresh bread and cheese