Preheat the oven to 350 degrees F. Lightly oil 6 (3-inch) individual cake pans.
Take the cooled polenta and pack into the prepared cake pans. Place the polenta cakes on a half sheet pan and bake in preheated oven for 15 to 18 minutes. Remove from the oven and cool for 15 minutes before unmolding.
In a large saute pan, heat 2 tablespoons olive oil and lightly cook the onions and pancetta, if using, until golden brown. Add the Brussels sprouts and thyme sprigs. Place in preheated oven and roast until soft, stirring occasionally to prevent burning. Remove the thyme.
In a separate pan, combine the baby carrots with equal parts oil and water to cover. Slowly bring to a simmer and cook until tender. Remove the carrots from the oil and combine with the Brussels sprouts.
To finish, reheat the polenta cakes in the oven for 10 to 12 minutes. As the polenta is cooking, slowly reheat the Brussels sprouts and carrots. Just before serving, place the polenta cakes in a bowl. Finish the Brussels sprouts and carrots with the red wine vinegar and salt and pepper, to taste. Arrange the vegetables around the polenta cakes in the bowl
This recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.