Preheat your oven to 350 degrees F.
Mix together all the ingredients for the Garlic Butter Seafood Boil Sauce in a small bowl, set aside.
1 cup 2 sticks butter, melted, ¼ cup white wine, ¼ cup Old Bay seasoning, ¼ cup chicken broth, 1 tablespoon garlic powder, 1 tablespoon onion powder, A hearty pinch of red pepper flakes, Juice of 1 lemon
Place all the thawed seafood, potatoes, corn, sausage, onion quarters ,and garlic halves into your oven bag and place that into a baking dish.
1 pound 13-15 jumbo shrimp, 1 pound snow crab leg clusters, 2 lobster tails, 4 ears of corn, 2 lbs baby potatoes, 12 ounces Andouille sausage, 1 yellow onion, 1 head of garlic
Pour all of the garlic butter sauce over the seafood and toss around gently to cover the seafood in the seasonings and butter.
Tie the bag shut with the tie that came with the oven bag (or use butcher's twine if you lost it).
Bake seafood for 30-40 minutes in your preheated oven. You want the potatoes to be fork tender and the shrimp pink and slightly curled in.
Carefully open the bag and serve your seafood boil in the baking dish!