Step 1Melt the butter in a deep heavy skillet over medium heat. Add the onion and garlic and saute until soft, about 5 minutes. Add the rice and salt and stir until coated. Stir in the vermouth or wine. Cook, stirring constantly, until all the wine is absorbed.
Step 2Add 1 cup of the stock and cook, stirring, until all the liquid is absorbed. Repeat with the remaining stock, cooking until the rice is al dente, 20 to 25 minutes. Remove from the heat and stir in the pepper and cheese, blending well. Cool slightly, then stir in the sage, again blending well.
Step 3Butter an 8-inch-square baking dish. Scrape the rice into it, smoothing the top completely. Chill uncovered until completely set, about 2 hours (or overnight).
Step 4Just before serving, heat a large nonstick skillet over medium-high heat. Line a platter with parchment paper or waxed paper and set it close by.
Step 5Using a small sharp knife, cut the chilled risotto into 1-inch squares. Using a small spatula, carefully remove each square from the dish and transfer to the hot skillet. Brown on both sides, turning with tongs or a small spatula. Transfer to a serving platter. Serve hot or at room temperature.