Tomato butter rice with black lime

Ingredients

• 80g unsalted butter
• 1 large onion, finely chopped (220g)
• 3 garlic cloves, thinly sliced
• 200g cherry tomatoes, halved
• ½ tbsp tomato paste
• 2 black limes, 1 finely ground, 1 pierced with a knife
• 1 tsp cumin seeds, lightly crushed
• 8 cardamom pods, bashed open
• ½ tsp ground cinnamon
• 250g basmati rice, rinsed and drained
• 550ml boiling water
• Fine sea salt