To split and clean a lobster, lay the lobster on its back and run a knife down the middle of the lobster all the way to the tail, but do not split the tail fan. Open up the cavity and remove the roe and intestinal matter. Give the cavity a gentle rinse.
Preheat oven to 375°.
Sauté onions, garlic and shallots in butter for about 10 minutes. Add sherry and reduce by half. Add scallops and cook for five minutes. Add shrimp and cook for another five minutes. Take off heat and allow to cool for 30 minutes.
In a large mixing bowl, mix together the Ritz cracker crumbs, Panko breadcrumbs, crabmeat, salt and pepper and chopped parsley. Add cooked seafood and mix all ingredients well.
Run a skewer from the tail to the head of the lobster to prevent from curling in the oven. Fill cavity of the lobster with the stuffing, but do not pack too firmly. Sprinkle a few crumbs on top and drizzle with melted butter. Bake for 30 minutes.