Melt the butter in a large skillet over medium heat. Add the onion and garlic and cook for 3 to 4 minutes, stirring occasionally, until onion is soft and lightly browned. Stir in the flour and cook for 1 minute.
Slowly pour in the wine, stirring constantly. Add the salt, pepper, and thyme. Simmer for 5 minutes, stirring occasionally.
Stir in the cream and parsley and simmer for an additional 3 minutes. Remove from heat and stir in the Parmesan cheese.
In a lightly greased 2-quart baking dish, layer the scallops and sauce. Sprinkle with the bread crumbs. Bake for 25 minutes, or until scallops are cooked through and the top is lightly browned.
Interesting Facts
Coquilles St. Jacques is a classic French dish.
It is traditionally served with a creamy white wine sauce.
The dish is often served in individual scallop shells.
It is believed to have originated in the 19th century.