Pat the salmon dry with paper towels.
This helps you get a better sear. Season both sides with salt, pepper, garlic powder, and paprika.
Make the sauce. In a small bowl, whisk together sour cream, mayonnaise, lemon juice, lemon zest, dill, garlic, salt, and pepper.
Taste and adjust seasoning. Chill while you cook the salmon.
Heat a large skillet over medium-high heat. Add oil and butter.
When the butter is foamy and hot, place the salmon in the pan. If using skin-on, start skin-side down.
Sear without moving for 3–4 minutes, until the edges look opaque and the skin is crisp. Flip carefully and cook another 2–4 minutes, depending on thickness, until the center is just turning opaque.
Aim for 125–130°F (52–54°C) for medium.
Transfer the salmon to plates and rest for 2 minutes. Spoon the lemon dill sauce over the top. Finish with extra dill and a squeeze of lemon.
Serve with your favorite low-carb sides like roasted broccoli, sautéed spinach, or cauliflower rice.