Bring water to a boil in a large saucepan and stir couscous, 1 tablespoon butter, and salt into boiling water. Reduce heat to low and simmer until couscous is tender and plump, about 10 minutes.
Heat remaining 1 tablespoon butter and olive oil in a saucepan over medium-low heat. Stir white wine, Parmesan cheese, garlic, and parsley into hot oil and butter. Cook and stir until parsley is tender and wilted, 3 to 5 minutes. Season with salt and black pepper.
Increase heat to medium-high and add scallops to sauce; cook until scallops just become opaque, 3 to 4 minutes. Divide couscous onto serving plates and top each serving with scallops in sauce.
Sprinkle each portion with 1 teaspoon Parmesan cheese and a pinch of fresh parsley.
