Make the ragù: Heat the oil in a thick pan.Add the onion, garlic, salt, and pepper. Cook, stirring occasionally, until the vegetables are soft, about 5 minutes. Add the seared sausage, season with the remaining spices.
* Pour in the wine to deglaze the pan and Cook until the wine is almost fully evaporated.
* Add the tomato paste and stir to coat. Add the tomatoes and their juices, broth, thyme, and pepper flakes. Bring to a boil, then reduce the heat to low and simmer, stirring occasionally, until the flavors meld, about 15-20minutes. Meanwhile, make the polenta.
* Make the polenta: Bring the water to a boil in a medium saucepan over medium-high heat. Whisk in the salt and cornmeal. Reduce the heat to low and whisk the polenta continuously until slightly thickened and no longer sticking to the bottom of the pan, 2 to 3 minutes.
* Cover and continue cooking, stirring and scraping the sides of the pan every 10 minutes, until the polenta is soft and creamy, 15-20minutes total. Remove from the heat and stir in the butter until fully melted.Serve the ragù over the polenta.