Preheat oven to 250°C / 482°F.
Clean the sardines by removing any scales and rinse well.
Cover you oven's tray or a sheet pan with a piece of parchment paper.
Place the sardines one next to the other.
Cut the garlic cloves to very thin slices and toss on top of the sardines here and there.
Dizzle with olive oil. Sprinkle the oregano, kosher salt, and pepper on top.
Cook the sardines for approximately 15 minutes until they get nice and roasted on top. There is no need to flip the fish while it cooks.
Serve with a few drops of freshly squeezed lemon on top.