Rinse the salmon fillets under cold water and pat them dry with paper towels. This helps to ensure the skin gets crispy when cooked.

In a small bowl, combine the salt, black pepper, garlic powder, and the zest of the lemon. Mix well to create a flavorful spice blend.

Rub the spice mixture onto the flesh side of the salmon fillets, ensuring they are evenly coated. This step is crucial for flavor.

Heat a cast iron skillet over medium-high heat and add the olive oil. Make sure the oil is hot before adding the salmon.

Once the pan is hot, place the seasoned salmon fillets in the skillet, skin side down. Cook for 3-4 minutes without moving them, until the skin is crispy and golden brown. Don't rush this step; the crispy skin adds to the enjoyment!

Using a fish spatula, carefully flip the salmon fillets and cook for an additional 2-3 minutes. If your salmon is particularly thin, it may only need 2 minutes on this side.

After flipping, add the butter and minced garlic to the pan. As the butter melts, spoon the garlic butter over the salmon fillets for extra flavor. Squeeze in the juice from half of the lemon for a zesty finish.

Use an instant-read meat thermometer to check the salmon's doneness; it should reach 125°F for medium-rare. This will typically take about 2-5 minutes, depending on the thickness of the fillets.

Watch for the salmon to change from pink to a more opaque white as it cooks. Trust your thermometer for the best results!

Once cooked, remove the salmon from the pan and garnish with a lemon wedge. This adds a fresh touch to your presentation.