In a small bowl, combine the panko, butter, a pinch of salt and the cheese.
In another small bowl, combine the thyme, garlic, lemon zest, a hefty pinch of black pepper and the cream.
Divide the scallops between two individual gratin dishes. Pour half of the cream mixture over each dish of scallops, then sprinkle each evenly with the panko mix. At this point, the dishes can be wrapped and refrigerated for up to 24 hours, or baked immediately.
Preheat oven to 400 deg F. Place the gratin dishes on a baking sheet and bake for 8 to 10 minutes, or until the cream is bubbling all over and the crumbs are browned.