You can't have Thanksgiving dinner without stuffing. Classic flavors, a moist-but-not-soggy texture, and a touch of sweetness will make this Instant Pot stuffing a new family favorite.
Program a 6-quart electric pressure cooker to sauté on normal heat. Add sausage; cook, stirring to break into large pieces, until browned, about 8 minutes. Using a slotted spoon, transfer sausage to a plate lined with paper towels. Heat oil in cooker. Add onion, celery, and garlic; cook, stirring often, until softened, 6 to 8 minutes. Transfer onion mixture to a large bowl.
Add cooked sausage, stuffing mix, cornbread, chicken broth, rice, eggs, sage, poultry seasoning, salt, and pepper to bowl with onion mixture; stir to combine. Spoon mixture into a lightly greased (with cooking spray) 7-inch (1 1/2 quart) soufflé dish.
Insert steamer rack into cooker; add 1 cup water. Place soufflé dish on rack. Close and lock lid of cooker; turn pressure release valve to sealing position. Program cooker to cook on manual on high pressure for 20 minutes. Allow cooker to release pressure (steam) “naturally” for 5 minutes. Turn pressure release valve to venting position to release remaining pressure from cooker until float valve drops; carefully remove lid.
Carefully remove soufflé dish from cooker. (Optional: Preheat boiler with oven rack 6 inches from heat. Broil stuffing until top is golden brown and crisp, 3 to 4 minutes.) Sprinkle with parsley. Let stuffing stand 20 minutes before serving.