1. Melt 2 tablespoons butter in a large Dutch oven over medium heat. Add next 3 ingredients; cook 5 minutes. Stir in flour; cook 1 minute. Add potatoes and next 5 ingredients; bring to a boil. Cover, reduce heat to low, and simmer 15 minutes or until potatoes are tender. Remove from heat.
2. Melt remaining 1⁄2 cup butter in a small skillet over medium-low heat. Cook 3 to 4 minutes, stirring constantly, until butter is golden brown and fragrant. Stir browned butter, peas, and crabmeat into vegetable mixture.
3. Unroll pie crusts on work surface; invert 6 (10-ounce) ramekins or custard cups onto pie crusts. Cut around edges of ramekins with the tip of a sharp knife to make circles. Spoon crab mixture evenly into ramekins. Whisk together egg and 1 tablespoon water. Brush pie crust circle edges with egg wash; place 1 circle, egg wash side down, over crab mixture in each ramekin, pressing down to seal to 4 slits in each crust to vent. Place on a foil- or parchment-lined baking sheet.
4. Bake at 375° for 25 to 30 minutes or until golden brown.