1 thumb-sized piece ginger, peeled and finely grated
1/2 cup (100 grams) fat-free natural yogurt
Rogan josh sauce:
6 tablespoons (90 milliliters) cooking oil
1 onion, chopped
2 tomatoes, chopped
1 bunch fresh coriander, chopped with stem included
1 red chili, seeded and roughly chopped
1 teaspoon (5 milliliters) black peppercorns, roughly ground
2 teaspoons (10 milliliters) red chili powder
1 teaspoon (5 milliliters) saffron
1 teaspoon (5 milliliters) rose essence
2 teaspoons (10 milliliters) garam masala
1/4 teaspoon (1 milliliter) salt
1 teaspoon (5 milliliters) coriander cumin powder
2 cups (480 milliliters) warm water
2 tablespoons (30 milliliters) tomato purée
Fresh coriander leaves
For the marinade:
Add canola oil, mustard oil, dry fenugreek leaves, cinnamon sticks, mace flowers, cardamom pods, bay leaves, crushed nutmeg, cloves, onion, garlic, and ginger to a food processor. Blitz until the mixture becomes a paste.
Add paste to yogurt and stir.
Cover the lamb with the mixture, then refrigerate for two hours, until the lamb gets tender.
For the rogan josh sauce:
Heat oil in a large saucepan over medium heat, then add onion and sauté until golden brown.
Add chopped tomatoes slowly, stirring as you do. Cook for 15 minutes.
Add the coriander, red chili, ground peppercorns, chili powder, saffron, rose essence, garam masala, salt, coriander cumin powder and stir together, then cook for another ten minutes.
For the lamb:
Add lamb to the saucepan with the rogan josh sauce then sauté for ten minutes over medium heat.
Add the tomato purée and stir.
Add the warm water, cover with a lid, and simmer for 40-50 minutes, until cooked through.