Preheat oven to 325 degrees. Season short ribs generously with salt and pepper on every side. Heat oil in large dutch oven on medium-high heat. When oil is hot, add ribs (cook in batches, if necessary); cook until browned on all sides (approx. 2-3 minutes per side). Remove ribs to a platter.
Place Dutch oven back on the heat. Once pan is hot, add carrots, celery and onions. Sautè veggies, stirring often, for 3-4 minutes, scraping up any bits of browned beef bits left on bottom of pan (they will add flavor!). Pour in red wine; simmer 2-3 minutes. Add beef stock and sprigs of thyme. Place short ribs back into pan. Make sure ribs are mostly covered with liquid (add more beef stock or water, if necessary) to ensure only the tops of the ribs are left uncovered. Cover pot, place in preheated 325 degree oven, and bake for 2 1/2 - 3 hours.
OPTIONAL STEP 1: This is optional, but one I definitely recommend. When done baking, transfer ribs (without liquid) to a sheet pan; Place sheet pan 5 inches under broiler and broil for 4-5 minutes to crisp up the outside. Watch ribs closely to make sure they don't burn! When done, cover ribs with foil; keep warm.
OPTIONAL STEP 2: ( I did this while ribs were in broiler). Make a slightly thick pan sauce using liquid from the dutch oven. Pour liquid and veggies from pan into a large strainer which is sitting on top of a bowl or pan (to catch the juice). Return liquid to the Dutch oven (reserving veggies). Cook on medium-low until liquid reduces (8-10 minutes). Once reduced, whisk 2 Tbsp. flour w/ hot water (1/4 cup) in separate container; whisk this into sauce while cooking, to thicken it a bit.
Make polenta, by bringing water, milk and salt to a boil in a medium pan. While whisking, SLOWLY add the polenta or corn meal; continue whisking ingredients together and cooking for 2-3 minutes, until polenta begins to thicken. Reduce heat to simmer and cook until it becomes thick, but still creamy in texture. Add butter and grated Parmesan cheese; stir them in until melted and fully combined.
To serve, spoon hot polenta into individual serving bowls, then place 1-2 short ribs and a few of the cooked veggies on top. Garnish with a couple spoonfuls of pan sauce, and a sprig of fresh thyme over ribs, then serve, and enjoy!
Beef Short Ribs With Parmesan Polenta https://www.thegratefulgirlcooks.com/beef-short-ribs-parmesan-polenta/