MAKE THE SALAD
Bring the chicken stock to a boil in a medium saucepan. Lightly oil a shallow 8-inch bowl. Whisk the polenta and 1/2 teaspoon of salt into the stock and cook over low heat, stirring often, until the polenta thickens and begins to pull away from the side of the pan, about 12 minutes. Stir in the Parmesan cheese. Remove from the heat and season the polenta with salt and pepper, then gently fold in the diced sweet potato. Spoon the polenta into the prepared bowl and smooth the surface. Cover with plastic wrap and refrigerate until firm.