Combine the chicken stock, 1/2 c water, and the garlic in a large saucepan and bring to a full boil over high heat. Slowly add the cornmeal while whisking constantly to ensure there are no lumps. Switch to a wooden spoon, add 1 1/2 tsp salt and 1 tsp pepper, and simmer over low heat for 15 minutes, stirring often, until the polenta is thick but still creamy. (The timing will depend on the cornmeal you use). Be sure to scrape the bottom of the pan with the wooden spoonso that the bottom does not burn.
Meanwhile, heat the butter in a large (12-inch) saute pan over medium heat. Add the corn and cook for 5 to 8 minutes, depending on the starchiness of the corn, until the corn is cooked through and starting to brown around the edges of the pan.
Off the heat, stir the corn, Parmesan and creme fraiche into the polenta. Taste for seasonings and serve hot.
Notes
Make Ahead: Prepare the polenta completely and refrigerate for up to a few days. Spoon into a saucepan with extra chicken stock or water and reheat over low heat until creamy and hot.