Fish: In a small dish, stir together seasonings: 1/2 tsp cumin, 1/2 tsp cayenne pepper, 1 tsp salt and 1/4 tsp black pepper and evenly sprinkle the seasoning mix over both sides.
2. Lightly drizzle fish with olive oil and top each piece with a dot of butter.To make the crema/ white sauce: 1/2 cup greek yogurt/ sour cream, 1/3 cup Mayo, 2 Tbsp lime juice (from 1 medium lime), 1 tsp garlic powder or fresh garlic, 1 tsp Sriracha sauce, or to taste in a medium bowl or a large measuring cup and whisk together until well blended.