The night before you want to cook the grits, place them in a heavy-bottomed saucepan, cover with the water, stir, wait a minute, then tilt the pan to skim off any chaff and hulls. Cover and set aside.
The next day, bring a kettle of water to a boil and set aside off the heat. Bring the grits to a boil and lower to a simmer, stirring, until it becomes thickish (5 to 8 minutes). Cover with the lid, lower to the lowest setting, and every ten minutes add 1/4 to 1/2 cup of the hot water, stirring to thin it out, and continue this process — covering, thickening, adding water — until an hour’s gone by. Taste for doneness and if they’re still a bit crunchy, keep going until they’re creamy and smooth. Off the heat, season with salt, add the butter and cheese, and beat beat beat until thoroughly incorporated. Put the lid on and set aside.
While you’re cooking the grits, place the shrimp shells in a pot with the olive oil and half the garlic. Toast on medium heat until it becomes fragrant, then add four cups of water. Bring to a boil, lower to a simmer, and reduce for twenty to thirty minutes until you have 2 cups of liquid. Strain and set aside.
In a large skillet, add your bacon and vegetable oil, turn heat to medium, and cook, letting the bacon render. When the bacon is good and crisp, remove to a paper towel lined plate. Pour off the bacon fat (save for another use), add the butter, and when melted, add the onion, the green pepper, and the rest of garlic with a pinch of salt. Cook until the onion is translucent, then add the tomato paste and toast a little in the fat. Add the tomato, another pinch of salt, and stir.
Whisk 2 tablespoons of the shrimp stock with the 1 tablespoon of flour. Add the shrimp stock to the skillet, plus the flour mixture, stir all around and cook at a simmer until thickened to your liking. Taste here — adjust with salt and Tabasco — then add your shrimp and cook for just two minutes or less; just until the shrimp are cooked through.
Ladle the grits into bowls, smooth out, then top with the shrimp and lots of the sauce. Sprinkle with the bacon and the chives or parsley and serve right away.