Add the onion, garlic, tomato paste, crushed tomatoes, red wine, beef stock, bay leaves, dried herbs, sugar and mushrooms to the slow cooker. Season well with pepper. Mix everything together.
1 brown onion, 4 cloves garlic, 4 tbsp tomato paste, 400 g canned crushed tomatoes, 0.667 cup red wine, 0.667 cup beef stock, 3 bay leaves, 1 tbsp italian herbs, 1 tsp caster sugar, 350 g mushrooms