BBC Food - Recipes - Onion masala sauce

Ingredients

• 30g/1oz root ginger , peeled
• 30g/1oz garlic cloves, peeled
• 2 tbsp vegetable oil
• 2 black cardamom
• 10 black pepper corns
• 3 cloves
• 4 green cardamom
• 2 tsp cumin seeds
• 2 cinnamon sticks
• 1 bay leaf
• 500g/1lb 2oz onions , chopped
• 1 tbsp ginger garlic paste (from above)
• 1 tsp ground turmeric
• ½ tsp red chilli powder
• 1 tbsp ground coriander
• 1 tsp garam masala
• salt , to taste
• 2 tbsp tomato purée