Step 1: Prepare the Pie Crust

1. In a large mixing bowl, combine flour and salt.
2. Cut in the chilled butter using a pastry cutter or fork until the mixture resembles coarse crumbs.
3. Gradually add ice water, 1 tablespoon at a time, until the dough comes together.
4. Form the dough into a ball, wrap it in plastic wrap, and refrigerate for at least 30 minutes.
5. Preheat oven to 375°F (190°C).
6. Roll out the dough on a lightly floured surface and fit it into a 9-inch pie pan.
7. Prick the bottom with a fork and pre-bake the crust for 10 minutes. Remove from oven and set aside.

Step 2: Cook the Shrimp

1. Heat butter in a skillet over medium heat.
2. Add onions, bell peppers, and garlic. Sauté for 2-3 minutes until softened.
3. Add shrimp, Old Bay seasoning, paprika, cayenne (if using), salt, and black pepper.
4. Cook for 3-4 minutes until the shrimp turn pink.
5. Remove from heat and let cool slightly.

Step 3: Prepare the Filling

1. In a large mixing bowl, whisk together eggs, heavy cream, and milk.
2. Stir in shredded cheddar cheese and mozzarella cheese.
3. Add the cooked shrimp mixture and stir well to combine.
4. Mix in fresh parsley and lemon juice for extra flavor.

Step 4: Assemble the Pie

1. Pour the filling into the pre-baked pie crust, spreading it evenly.
2. Bake at 375°F (190°C) for 30-35 minutes, or until the center is set and the top is golden brown.

Step 5: Cool and Serve

1. Let the pie rest for 10 minutes before slicing.
2. Garnish with extra parsley and serve warm.