Line the bottom and sides of a half sheet pan with plastic wrap.

Bring the chicken broth to a boil, season with salt & pepper. Slowly add the cornmeal to the boiling stock, stirring constantly. Reduce heat to a simmer, stirring frequently. Cook polenta for 25 minutes. Add water if polenta thickens too much. When polenta has finished cooking it will pull easily away from the sides of the pan. Remove from heat and add the Parmesan, butter and thyme. Stir and taste. Season with additional salt and pepper, if needed.

Pour the polenta on to the plastic wrapped sheet pan. You will only use one half of the sheet pan. The polenta should be a little less than a half inch thick. Smooth top and side of polenta with a spatula. Let cool. Cover with plastic wrap and refrigerate for at least an hour or up to 24 hours.

Heat gas grill to medium high. Cut polenta in to triangles. You should be able to get 16 triangles. Oil the grill. Place polenta on grill. Cook for 2-3 minutes. Turn the polenta 45 degrees and continue cooking on the same side for another 2-3 minutes. Do the same for the other side of the polenta. Remove from grill, set to the side. They will be served at room temperature.