In a small bowl, combine the flour and salt. In a large bowl, beat the 1 cup of butter and cream cheese until fluffy, about 2-3 minutes. Slowly beat in flour mixture until dough starts to form.
Dive the dough in half and shape into 2 rounds. (You can store the other half in the freezer in a freezer bag for up to 1 month for another use, or another quiche!). Cover and refrigerate the dough round for about 1 hour, or until well chilled.
Meanwhile, in a medium bowl, combine the crabmeat, panko, onion, and bell pepper. Stir in parsley, mustard powder, salt, pepper, and cayenne pepper. Toss with melted 3 tablespoons of butter and heavy cream. Mix well and fold in eggs and cheese.
Roll out dough on a floured surface to about 1/8 inch thickness. Make large enough to fit a normal sized pie pan. Grease pie pan and preheat oven to 350F.
Set dough in pan and place pie weights or dry beans atop of dough. Bake for about 10 minutes, or until starting to brown.
Add crabmeat mixture and bake for about 25-30 minutes longer, or until filling is set. Let cool for about 5 minutes and serve!