Cut the vegetables into similarly-sized chunks, and toss in the olive oil with some salt and pepper. Spread evenly on a baking sheet and bake for 20-30 minutes, or until tender.
At the same time, prepare the polenta. Bring the milk, chicken stock, butter, and ½ tsp salt to a boil in a large saucepan.
Add the cornmeal, whisking to avoid clumping. Whisk until the mixture thickens, then turn the heat down to medium-low.
Continue to cook, whisking frequently, until very thick — about 20 minutes. Add the cheeses and mix until fully melted and incorporated.
Pour the polenta into a non-stick (or buttered) skillet. Reduce the oven temperature to 350 F and bake the polenta for 15-20 minutes, until it is beginning to set up. At this point your vegetables will have been done and sitting out for a little while, so add them on top of the polenta and bake for another 5-10 minutes.
Season with salt and pepper as needed.
Recipe by The Kitchen Paper at http://c02.ddd.mwp.accessdomain.com/creamy-fontina-polenta-roasted-vegetables/