Bring a heavy bottom pan or cast iron to high heat and add a high smoke point oil like peanut. Season the meat with salt and pepper on all sides, and sear in the pan, about 3-5 minutes per side until browned, on all six sides. Transfer to a baking dish.
Mix the sauces together and pour over the meat. Stir in the garlic cloves. The meat should be covered about 2/3 of the way with the sauce. Preheat the oven to 300 and cook the meat uncovered for about 3 hours, flipping once per hour. If you see it starting to burn a little too soon, turn it down.
When there is about an hour left on the beef, start the grits.
First, if you have good quality stone ground grits, there might be chaff in the mixture. Add them to a large bowl and fill with water. Move the grits around with a spoon and all the stuff that floats to the top is the chaff. Use a strainer spoon to skim it off the top. Then strain the grits. Some people soak the grits longer as well.
Bring the milk to a simmer and whisk in the grits. Stir in the salt. Continue to stir and cook at a medium low simmer. Cook about 40 minutes, stirring occasionally.
Stir in the corn next, especially if you are using frozen corn. Cook 3 minutes. Stir in the butter, cheese, garlic powder, and gochugaru. Stir for 1 minute. Add in more milk if needed to thin out the grits.
Remove from heat. Serve the grits in shallow bowls. Top with short ribs, and additional short rib cooking liquid. Top with sesame seeds and gochugaru