In the bottom of a 6-quart or 8-quart slow cooker, place and layer the sliced onions.

In a large bowl, combine the boneless chicken, bell pepper, carrots, tomato sauce, tomato paste, lemon juice, garlic, ginger, curry powder, garam masala, and salt. Toss until well combined.

Add the saucy chicken mixture to the slow cooker over top of the sliced onions.

Dot the pieces of butter over the top of the marinated chicken mixture.

Place the lid on the slow cooker and cook on high for 4 ½ hours or on low for 6 ½ hours.

After the time is up, remove the lid, stir all ingredients until well combined, and turn off the slow cooker.

When the liquid stops simmering and steaming (after about 5-10 minutes), stir in the yogurt and the half-and-half.

Serve over hot cooked rice or cauliflower rice, and/or with naan bread, and garnish with chopped fresh cilantro and toasted sesame seeds.

Place a large pot or Dutch oven over medium-high heat. Add 2 teaspoons olive oil to the pot and swirl to coat.

When the oil is hot, add the onions, bell pepper, and carrots. Cook for 7-8 minutes or until the veggies are tender, stirring occasionally.

Add the chicken pieces, spices, tomato sauce, tomato paste, and 1 cup water.

Dot the top of the marinade mixture with the butter and cover with a lid.

Simmer until the chicken is cooked through (which will take about 20 minutes).

When the chicken is cooked through, remove the lid, stir all ingredients until well combined, and turn off the heat.

When the liquid stops simmering and steaming (after about 5-10 minutes), stir in the yogurt and the half-and-half.

Serve over hot cooked rice or cauliflower rice, and/or with naan bread, and garnish with chopped fresh cilantro and toasted sesame seeds.

Place the onions, chicken, bell pepper, carrots, tomato sauce, tomato paste, lemon juice, garlic, ginger, curry powder, garam masala, salt, and butter into the inner pot of the Instant Pot. Stir until well mixed.

Add ½ cup of water to the chicken mixture and stir again until everything is combined and there is some of the saucy liquid under the ingredients at the bottom of the Instant Pot.

Place the lid on the Instant Pot and lock into place. Cook on high pressure for 10 minutes.

When the cooking time is up, quick release the pressure and remove the lid. Stir well to allow the steam to escape.

Let the butter chicken sit in the Instant Pot to cool for 10 to 15 minutes, stirring occasionally to allow more steam to escape.

After 10 to 15 minutes, stir in the yogurt and half and half.

Serve over hot cooked rice or cauliflower rice, and/or with naan bread, and garnish with chopped fresh cilantro and toasted sesame seeds.