• 680g (3⅓ cup) plum tomatoes
• ¼ medium red onion
• 1 garlic clove, unpeeled
• 60ml (¼ cup) apple cider vinegar
• 2 tbsp granulated sugar
• 1 tsp whole mustard seeds
• 4 whole cloves
• ¼ tsp ground cinnamon
• ¼ tsp ground cumin