Simmer the onions and garlic in 2 - 3 tablespoons olive oil until translucent. Add serrano chiles, cilantro stems, and tomatoes and simmer until tomatoes break open and are very soft. Puree in a blender until smooth. Remove and strain. Season to taste with salt and pepper.

Sauté the spinach in 1 - 2 tablespoons olive oil until wilted, about 3 - 4 minutes. Strain and reserve the liquid. Sauté the tomatoes, onion, and garlic in the remaining oil until the onion is soft and translucent. Add cumin, jalapeños, and reserved spinach liquid. Dissolve the cornstarch in chicken stock and stir into the mixture. Cook until thickened, about 2 - 3 minutes. Fold in the spinach and season with salt and pepper.

Brush the chicken breasts with olive oil and season with salt and pepper. Grill on an outdoor grill, or sauté in equal amounts of butter and olive oil, in a large skillet, about 3 - 5 minutes per side.

Put a large spoonful of the spinach mixture on top of each chicken breast. Top with goat cheese. Place under the broiler, about 8 inches from the element, to soften the cheese, about 1 minute.

Serve the chicken atop Saffron Rice, in the center of the plate. Pool the rest of the plate with the warm Tomato Salsa. Dilute the sour cream with a little milk and drizzle over the entire dish.