Start by patting the Mahi Mahi fillets dry with a paper towel. Season both sides with salt and black pepper. This step is crucial for adding flavor and ensuring a crisp sear.
Heat olive oil in your skillet over medium-high heat. Place the seasoned fillets in the hot pan and sear for about 4-5 minutes per side, until you get a golden crust. The fish should flake easily with a fork when done. Remove from the skillet and set aside.
Using the same skillet, add butter and minced garlic. Sauté for about 1-2 minutes until fragrant. Now, pour in the heavy cream, add lemon zest, juice, and thyme. Stir it all together and simmer for about 3-4 minutes, allowing the sauce to thicken slightly.
Return the fish to the skillet and nestle it into the sauce. Simmer for another 2-3 minutes so the flavors meld together and the fillets are warmed through.
Plate the fillets and generously spoon the sauce over each piece. Finish with a sprinkle of fresh parsley and serve immediately.