Chimichurri: Add all the ingredients listed under "For Chimichurri" to a food processor. Lock the lid and pulse until it reaches a semi-fine consistency. Check for seasoning and adjust spices and acidity to taste.
Prepare Tray: Line a baking sheet with parchment paper. Reserve 4-5 thinly-cut lemon slices and spread the remaining cut slices across in the middle to make a bed for salmon.
Prepare Salmon: Place the salmon fillet on the lemon bed, skin-side up. Sprinkle ½ teaspoon salt + ½ teaspoon black pepper all over. Evenly spread about ¼ cup of the sauce over the salmon. Now flip the fillet such that the skin side is resting on the lemon slices.
Marinate Salmon: Liberally spread the chimichurri sauce over the salmon fillet, coating it entirely. Reserve the remaining sauce for serving. Top with reserved lemon slices spread across the filet. Place the entire tray in the refrigerator for 20-30 minutes.
Bake Salmon: Take the salmon out of the refrigerator. Preheat the oven to 375°F. Once heated, place the tray on the middle rack, and bake for 15-20 minutes, depending on the thickness of the fillet. (15-18 minutes for 1-inch thickness; 18-20 minutes for 1½-inch thickness). Note: Check the doneness 2-3 minutes earlier than the estimated cooking time to prevent overcooking. Salmon is done when it reaches 145°F on a meat thermometer inserted at the thickest part of the fillet (well-done), or 135°F for medium-well.(I prefer well-done).
Serve: Once done, rest the salmon for 5 minutes, then serve with the reserved chimichurri sauce along with your favorite side dishes, such as lemon pepper asparagus and roasted potatoes.
Video
Notes
Salmon skin: This is a personal choice. I prefer to make it without the skin as the fish absorbs the flavors of the marinade better like that.
Check for pin bones: Run your finger down the length of the salmon around the thickest part. Remove any unwanted pin bones with needle-nose pliers.
Internal temperature: Check for doneness using a meat thermometer inserted at the thicket part of the fillet. It should reach 145°F for well-done, or 135°F for medium-well doneness.
Marinate: If you cannot fit a baking tray in your fridge, transfer the marinated salmon to a gallon-size ziplock bag, and refrigerate for 20-30 minutes.
Prevent overcooking: Check the doneness 2-3 minutes earlier than the estimated cooking time to prevent overcooking.
Note: The nutrition facts below are my estimates. If you follow any diet plan, I recommend cross-checking with your preferred nutrition calculator.