Stuffed Zucchini Au Gratin

Ingredients

• • 1/2 lb (225 g) lean ground beef
  • 2 tablespoons (30 ml) olive oil
  • 1 onion, finely chopped
  • 4 oz (115 g) chopped white mushrooms
  • 2 cloves garlic, finely chopped
  • 1/2 cup (125 ml) chicken broth
  • 1/4 cup (60 ml) breadcrumbs
  • 4 to 6 large zucchini
  • 1 1/2 cups (375 ml) tomato sauce
  • 1 1/2 cups (375 ml) grated mozzarella
  • Salt and pepper