Osso Buco in the Slow Cooker

Name: Osso Buco in the Slow Cooker
Prep time: 20 min
Cook time: 8 h
Total time: 8 h 20 min
Cuisine: Italian
Ingredients: 1 tablespoon plain flour; salt and pepper, to taste; 3 thick slices veal shank, sliced for osso buco; 1 tablespoon butter; 1 tablespoon olive oil; 1 onion, roughly chopped; 1 large carrot, chopped; 1 stalk celery, chopped; 1 clove garlic, thinly sliced; 150ml chicken stock; 200g diced tinned tomatoes; 1 teaspoon fresh oregano, chopped; 1 bay leaf