Make the spice blend: In a small bowl, combine turmeric, ginger, cumin, coriander, cayenne, garlic powder and onion powder.

Toss the shrimp with 2 teaspoons of the spice blend and a light sprinkle of salt. Set aside.

Heat a large shallow skillet over medium-high. Add the ghee and cumin seeds, and toast until fragrant, about 30 seconds. Add the onion, cook until softened and translucent, stirring frequently, 5 minutes.

Add the remaining spice blend, stir and toast until fragrant, 30 seconds. Add the ginger, garlic and tomato paste. Stir and cook until the tomato paste deepens in color, about 1 minute. Reserve 1 tablespoon of the chopped tomato for garnish. Add the remaining chopped tomato, about half of the chopped cilantro and ½ cup water. Increase the heat to high and bring the sauce to a simmer. Cook the sauce, stirring until it thickens and reduces (about three-fourths of the original volume), 3 to 5 minutes. Season with salt.

Add the shrimp to the skillet all at once and stir to coat with the sauce. Add the spinach in two batches, wilting the first batch before adding the second, and season with salt. Cook on high heat, stirring occasionally, until spinach is softened, shrimp is cooked through and most of the liquid has evaporated, about 4 to 5 minutes. Stir in the heavy cream and adjust the seasoning to taste with more salt, if necessary.

Remove from heat and garnish with the reserved chopped tomatoes and the cilantro. Serve over steamed rice and warm, pillowy naan. Top the saag with green chile chutney, tamarind chutney or fresh kachumbari for a lovely pop of acid and heat.