1. Peel the onion and cut in half. Peel garlic and ginger. Place onion, garlic and ginger in the bowl fitted with the ultrablade knife and mix at speed 12 for 10 seconds. Scrape down the sides of the bowl.
2. Replace the ultrablade knife with the mixer. Add oil and launch the P1 simmer program at 270°F for 5 minutes. Cut the lamb into 1-inch pieces.
3. At the end of cooking, add curry paste, tomatoes and lamb. Launch the P2 simmer program at 200°F for 1 hour 30 minutes. Wash, trim and roughly chop the spinach. After 1 hour 27 minutes, stir in spinach and cook for remaining 3 minutes.
4. While lamb is cooking, prepare the rice according to package directions. At the end of the program, top lamb with mint and serve with rice.