Heat a large skillet over medium. Add in the oil and half the butter. Sprinkle the cajun seasoning over each piece of salmon and rub in gently with your hands to coat evenly. Place each piece of salmon in the skillet, skin side up and cook for 3 minutes, then flip over. Cook 3 more minutes, then remove the salmon and set aside.
Add in the rest of the butter to the skillet and once melted, sauté the garlic for about 20 seconds. Careful not to burn it! Stir in the the remaining 1 teaspoon of cajun seasoning, then heavy cream, parmesan cheese and parsley. Add the salmon back in to finish cooking. While cooking, spoon the sauce over the tops so that each piece is well coated.
Serve with your favorite veggie on the side! A little tip... if you're cooking for anyone who's not on Keto, you can add more heavy cream to the sauce and serve it to them over pasta.