Prepare vindaloo paste according to the recipe instructions. Set aside. (Recipe here)

Place lamb in a large bowl. Add vindaloo paste. Toss to coat. Cover and marinate in the refrigerator for at least an hour or overnight if possible.

Meanwhile heat oil in a large frying pan over medium-high heat. Add onions, and sauté, stirring occasionally, for about 2-3 minutes or until the onions are soft and translucent. Add chopped garlic, and sauté, stirring, for 1 minute or until fragrant.

Add ground turmeric, red chili powder, tomato paste, tomatoes and cider vinegar. Sauté, stirring occasionally, for 2-3 minutes or until the tomatoes break down and turn mushy.

Add lamb and sugar. Season with salt. Stir to combine. Cook, stirring occasionally, for about 10 minutes.

Pour in water. Stir.

Bring to the boil. Reduce heat to medium. Cover and simmer for about an hour or until lamb is cooked through and the sauce is thick.

After step 5, transfer the curry to slow cooker. Cover with lid. Cook for 4-5 hours on high or 7- 8 hours on low.

Turn on instant pot. In sauté mode, heat oil, and sauté onion. Add garlic and sauté for few seconds. Add ground turmeric, chili powder, tomatoes, tomato paste and vinegar. Sauté for 2-3 minutes or until tomatoes turn mushy. Add marinated beef and sugar. Add water. Stir to combine. Season with salt.

Put the lid on the instant pot. Select manual mode. Set the timer for 20 minutes. When done, let the pressure release naturally for 15 minutes. Remove lid. If there’s too much sauce in the curry, you can turn on the saute mode (without the lid), and cook a little longer to thicken it.