Gnocchi & tomato bake

INGREDIENTS

• 1 tbsp olive oil
• 1 onion , chopped
• 1 red pepper , deseeded and finely chopped
• 1 garlic clove , crushed
• 400g can chopped tomatoes
• 500g pack gnocchi
• handful basil leaves, torn
• half a 125g ball mozzarella , torn into chunks