Barbecued Steak with Portobello Mushrooms | Reader's Digest Australia

Ingredients

• 2 teaspoons olive oil
• 2 cloves garlic, minced
• 4 thin slices red onion
• 4 large portobello mushrooms, stems removed
• non-stick olive-oil cooking spray
• 2 boneless rib-eye steaks (about 350 g each)
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 3 small ripe tomatoes
• fresh chives or parsley, finely chopped