Preheat oven to 325 degrees F for the crust.

Blend softened butter and cream cheese in a mixing bowl until well combined.

Cut in the flour with a fork.

Divide the dough into 6 equal balls.

Chill the dough balls in the refrigerator for 1 hour.

Grease a 6-cup jumbo muffin tin with butter or nonstick cooking spray.

Pat each chilled dough ball into each muffin cup to form the crust.

Bake the crusts for approximately 8 minutes, or until golden brown.

Preheat oven to 350 degrees F for the filling.

In a saucepan over medium heat, melt butter.

Stir in flour to create a roux.

Slowly blend in half-and-half, stirring constantly to avoid lumps.

Continue stirring until the sauce thickens, but do not allow it to brown.

Add mushroom soup, sliced mushrooms, Parmesan cheese, and beaten egg to the sauce.

Stir to combine all ingredients.

Gently fold in the cooked, diced shrimp.

Add garlic powder to taste.

Pour the shrimp mixture into the pre-baked pie crusts.

Top each pie with buttered bread crumbs.

Bake for 15 to 20 minutes, or until the filling is brown and bubbly.

Let the pies cool for 10 minutes before removing them from the muffin tin.

Garnish each pie with a sprig of parsley before serving.