In a large saucepan over medium high heat melt the oil and butter. Add the onions and sauté for 5 minutes until golden. Add mushrooms, carrot, zucchini, red pepper, garlic, spinach, parsley, and sun dried tomatoes. Season with salt & pepper. Stir and place the lid on for 3 minutes to let it all sweat together. Remove the lid and add in the balsamic vinegar, vegetable stock, tomatoes, and the Primavera sauce. Throw in a bay leaf and simmer for 2 hours, stirring often. Taste and add salt and pepper as necessary.