In a skillet heat the skillet over high heat. Add the oil and the butter.
While the butter is melting combine all of the spice blend ingredients and season both sides of the mahi mahi. Add the mahi mahi to the hot pan. Cooking for 3-4 minutes per side. The time will vary according to the thickness and the internal temp should be 137°F or 58°C. Reduce the heat if it is browning too quickly. Once cooked removed from the pan and cover to keep warn.
Return the pan to the heat, reduced to medium-high, and add the shallots, cook until they are translucent about 2 minutes and then add the garlic. Cook for another minute. While the garlic is cooking add a couple tablespoons of the wine to the cornstarch and create a slurry and set aside.
Add the wine and stir to deglaze the pan, cook for a minute and add the cream, lemon juice, lemon zest, cornstarch slurry, thyme and parsley. Cook until reduced by half and has thickened slightly. Add the salt and pepper and stir to combine. Add the fish back to the sauce spoon the sauce over the fish and serve.