Italian-style beef stew

INGREDIENTS

• 1 onion , sliced
• 1 garlic clove, sliced
• 2 tbsp olive oil
• 300g pack beef stir-fry strips, or use beef steak, thinly sliced
• 1 yellow pepper , deseeded and thinly sliced
• 400g can chopped tomatoes
• sprig rosemary , chopped
• handful pitted olives