Combine the sugar, cornstarch, vinegar, and water in a small saucepan. Bring to a boil, then turn the heat down and simmer for 5 minutes. You should see consistent small bubbles.
1/3 cup granulated sugar, 1 tablespoon cornstarch, 1/3 cup white vinegar, 1/3 cup water
Turn the heat down to low, add the beets and cloves to the liquid, and cook uncovered for 30 minutes.
1 1/2 pounds beets, 3 whole cloves
Add in the butter, salt, cinnamon, and pepper. Taste and adjust seasonings as needed. Serve warm.
1 tablespoon unsalted butter, 1/4 teaspoon kosher salt, 1/4 teaspoon cinnamon, dash black pepper