Preheat the oven to 350 degrees F. Brush top of fillet with olive oil, sprinkle on seasonings and zest.
Lay into baking dish or lined baking sheet with skin side down. Top with slices of lemons.
Bake in preheated oven for 12 minutes, then switch to broil for the last 2 minutes if you want a bit of crisp on the top. This will give you a fork tender not over-baked fillet.
Optimal inside temp in thickest part should be 140 F when you take it out to rest. It will rise a few degrees above that when done to be perfectly tender.