Make it don't buy it: Baked beans

INGREDIENTS

• 1 400g tin haricot beans, drained
• 1 400g tin chopped tomatoes
• 1 clove garlic, crushed
• 1 onion, finely diced
• 1 olive oil
• tbsp cider vinegar
• 2 dark Muscavado sugar
• tsp black treacle
• 1 English mustard
• tbsp Salt and pepper to season