Cut the chicken breasts into small, equal-sized cubes and place them in a mixing bowl.

Season the chicken with salt and pepper.

Add turmeric, cumin, ground coriander, cayenne pepper, and garam masala to the chicken.

Add plain yogurt and grapeseed oil to the chicken, then mix thoroughly until all pieces are well-coated.

Heat grapeseed oil in a hot pan. Slice the red onion and add it to the pan with a pinch of salt to caramelize.

Crush cardamom pods with the side of your knife to release their fragrance and add them to the pan along with whole cloves.

Roughly chop the ginger and fresno chili, and slice the garlic. Add them all to the pan and stir.

Add butter to the pan to enrich the sauce. Then add garam masala, turmeric, cumin, and cayenne pepper to toast the spices.

Stir in the tomato sauce.

Pour in the heavy cream, stir to combine, and bring the sauce to a boil.

Season the sauce with a touch more salt and a squeeze of lemon juice, then taste and adjust seasoning if needed.

While the sauce simmers, heat another pan with oil and cook the marinated chicken until it gets a bit of color.

Transfer the hot sauce to a blender and blend on low, gradually increasing the speed until it's completely smooth.

For an extra velvety texture, pass the blended sauce through a fine-mesh sieve into a clean pan, using a ladle to push it through.

Add the cooked chicken and any remaining marinade from the pan into the smooth sauce.

Turn off the heat. Add a couple more knobs of butter, some fresh lemon zest, and freshly chopped cilantro, stirring gently to combine.

Serve the Butter Chicken in bowls, garnished with fresh cilantro leaves, alongside a bowl of steamed rice.