Mix the ricotta, bread crumbs, lemon zest, egg, and Scotch together in a bowl. Add more bread crumbs, if necessary—the mixture should be fairly firm, but light and moist. Shape into 8 ovals about 3 inches long and 1 inch thick. Let rest for 10 minutes.

Bring 3 inches of lightly salted water to a rolling boil in a large, deep-sided frying pan. Gently lower the gnocchi into the boiling water with a slotted spoon. Gently roll each over with a wooden spoon to cook evenly. After about 5 minutes, when the gnocchi float, they are done. Drain on paper towels.

Meanwhile, melt the butter and stir in the sage leaves, keeping the heat very low.

Arrange 2 gnocchi on each of 4 first-course plates. Spoon equal amounts of the sage butter over the tops and sprinkle with Parmesan cheese. Serve immediately.