Shrimp and Grits

Name: Shrimp and Grits
Prep time: 5 min
Cook time: 2 h 10 min
Total time: 2 h 15 min
Cuisine: Southern
Ingredients: 5 3/4 cups (1.4L) homemade or store-bought chicken stock, divided; 1 pound (450g) large shrimp, shelled (shells reserved); 3/4 pound (340g) mixed mushrooms, such as cremini, shiitake, and oyster, stemmed and thinly sliced (stems reserved); 3/4 teaspoon (3g) kosher salt, plus more for seasoning; 1/4 teaspoon baking soda; 1/4 teaspoon cornstarch; 1 cup grits, preferably stone-ground (see note); 1 cup grated Gruyère cheese (about 4 ounces; 115g); Freshly ground black pepper; 4 slices thick-cut bacon (about 4 ounces; 115g), diced; Vegetable oil (if needed); 1 medium shallot, minced; 2 medium cloves garlic, minced; 1/4 teaspoon cayenne pepper; 2 tablespoons (30g) unsalted butter, cubed; 1 tablespoon (15ml) fresh juice from 1 lemon; 2 tablespoons mixed minced fresh herbs, such as parsley, chives, and tarragon, plus more as garnish