Chef John's Cornish Pasty

Ingredients (14)

• + 4 cups bread flour add to pantry
• + 3 ounces cold lard add to pantry
• + 2 ounces cold butter add to pantry
• + 1 ½ teaspoons salt add to pantry
• + ⅔ cup ice water, or as needed add to pantry
• + 12 ounces beef skirt steak, cubed add to pantry
• + 1 cup diced Yukon Gold potatoes add to pantry
• + ½ cup diced onion add to pantry
• + ⅓ cup diced turnip add to pantry
• + 1 teaspoon freshly ground black pepper add to pantry
• + 1 pinch cayenne pepper add to pantry
• + 2 tablespoons butter, cut into 8 thin slices add to pantry
• ✓ 1 large egg, beaten
• ✓ 1 teaspoon water