Traditional Spanish Empanada

Name: Traditional Spanish Empanada
Ingredients: 3 cups all purpose flour (plain flour Australia and UK) (plus extra for dusting); 1 teaspoon sea salt (fine); 3/4 cup unsalted butter (cubed and chilled); 1 large egg (beaten); 6 tablespoons water (ice-cold ); 2 tablespoons olive oil (extra virgin); 1 large onion (finely chopped); 2 cloves garlic (minced); 1 large red pepper (red capsicum) (diced); 1/2 pound ground beef; 1 teaspoon smoked paprika; 1/2 cup tomato sauce; 1/4 cup green olives (sliced); 1 teaspoon salt (to taste); 1 large egg (for egg wash)