Look for "dry packed" not soaked, wet, or treated scallops. Dry packed scallops taste better and haven't been artificially plumped up with water.
- 2 pounds sea scallops (about 4 cups), fresh or thawed if frozen, dry-packed
- 1 cup dry white wine (such as a Sauvignon Blanc)
- 1/4 teaspoon salt (omit if using salted butter)
- 6 tablespoons unsalted butter, divided
- 1 1/2 cups finely chopped onion
- 2 1/2 tablespoons flour
- 1/2 cup fine breadcrumbs
1 Preheat oven to 400°F.
2 Simmer the scallops on the stovetop: Place scallops in a medium sauté pan. Add the wine and a pinch of salt. Bring to a boil, reduce heat to a simmer, cover and simmer for 4 minutes, no longer.
Transfer the scallops to a 1 1/2-quart casserole baking dish using a spatula and arrange in a single layer. It's ok if they're a little crowded or if a few overlap. Pour off the cooking liquid to a separate container and reserve.
3 Cook the onions: Heat 3 tablespoons butter in the sauté pan on medium heat. Add the onions and cook until wilted, a couple minutes.
4 Make the sauce: Slowly sprinkle the flour over the butter onion mixture and stir to combine. Let cook for a minute or two. Then add the cooking liquid over the butter onion mixture, whisking vigorously while you do so.
As soon as the sauce is thickened, add it to the scallops in the casserole baking dish. Stir gently to fully incorporate the scallops into the sauce.
5 Bake: Sprinkle breadcrumbs over the scallops and dot with the remaining 3 tablespoons butter. Bake in the oven at 400°F until bubbly and brown, approximately 15 minutes.
Serve with lemon slices.