In the inner pot of the Instant Pot, layer potatoes, sausage, and corn in that order. Add garlic and bay leaves. Place the shrimp on top of the corn and then pour the beer or stock into the inner pot. Be sure to use 1 cup of beer/stock for a 6-Quart Instant Pot and 1.5 cups of beer/stock for an 8-Quart Instant Pot.
Pour 1 ½ tablespoons of the lemon juice over the shrimp and then sprinkle with Old Bay.
Place the lid on the Instant Pot and be sure the vent knob is sealed. Set to cook on high pressure for 2 minutes.
Once cook time has elapsed, do a quick release of pressure.
Combine the melted butter, parsley, and remaining ½ tablespoon of lemon juice together in a small bowl. Pour over the shrimp mixture and toss to coat, removing the bay leaves as you come across them.
Shrimp: You must use raw jumbo frozen shrimp for this timing of this recipe to work. Precooked shrimp or smaller shrimp will result in overcooked shrimp. You can use frozen unpeeled jumbo shrimp if desired. The peels will add flavor to the overall dish and helps to keep the shrimp juicy. Be sure your shrimp is still jumbo size and frozen and the cooking time will remain the same. Potatoes: While red potatoes are traditional, feel free to use Yukon Gold or baby new potatoes. For larger red or gold potatoes, quarter the potatoes. For smaller potatoes, cut them in half. Lemon Juice: Do NOT substitute jarred lemon juice for the fresh lemon juice, the flavor will be overly bitter and artificial.For the Old Bay: It is best to use my homemade blend or store-bought Old Bay. However, you can substitute the Old Bay with the following: ½ tablespoon celery seed, ½ tablespoon paprika, ½ teaspoon salt, ½ teaspoon ground dry mustard, ⅛ teaspoon pepper, a pinch of cayenne, and a pinch of nutmeg, cinnamon, ground ginger, and ground cloves.Cajun-Style Shrimp Boil: Instead of using 2 tablespoons of Old Bay Seasoning, I recommend using 1 tablespoon each of Old Bay and Cajun Seasoning.Beer: If using beer, opt for a light lager like Corona or Coors Light. If you do not care for beer, or to keep this recipe gluten-free, use low-sodium seafood stock or chicken stock in place of the beer. As a last resort, use water. Use 8 ounces, or 1 cup, for a 6-quart Instant Pot and 12 ounces, or 1.5 cups, for an 8-quart Instant Pot. Storage: Store cooled leftovers in a sealed container for up to 3 days. The leftovers do not freeze well.