Because sockeye salmon has such low fat content, compared to other types of salmon, it can be easily overcooked and dry. The slow roasting method renders a beautifully juicy and moist sockeye salmon. Its thin fillet also makes the slow roasting time actually very quick!
Remove the pin bones and skin from the salmon, if you don't want to deal with them later.
Place the salmon on an oiled or parchment lined baking sheet, skin side down.
Rub the oil over the salmon flesh. Season with the salt on top.
Lay the lemon slices over the top of the fillet.
Bake for 15-20 minutes or the internal temp is 125 degrees F.
Serve with lemon wedges and a dollop of butter, if using.
Notes
To make this even quicker, you can slow roast at 250 degrees F for 10-15 minutes. Just keep an eye on it because the sockeye salmon is so thin, it can go from slow roasted and silky to well done very quickly.
125 degrees F for salmon is medium rare. The sockeye salmon might seem "raw" in the middle because it hasn't turned opaque or that pastel orange color. But it is cooked if it flakes easily with a fork. If it's actually still raw, you won't be able to flake it with a fork; you'll just be able to prick the flesh with a fork.
Let's say you do cook it to 145 degrees F. That is technically "well done". The flesh will be completely pastel orange like you pan-seared it or baked it at 350 degrees F. However, with the slow roast method, it will still be moist and juicy even though it's well done.
Slow roasting also works with thicker salmon filets such as King and Atlantic salmon varieties. However, it will take 40-50 minutes long.
Store in an airtight container for 2-3 days in the fridge. To reheat, you can again put it in a 250 degree oven to warm up for about 5-10 minutes.