1/2 cup all-purpose flour
Kosher salt and freshly ground black pepper
4 large soft-shell crabs, preferably jumbo or “whale” size, cleaned
1 stick (8 tablespoons; 120g) unsalted butter, divided
1 tablespoon drained capers
2 tablespoons (30ml) fresh lemon juice from one lemon
1 tablespoon minced flat-leaf parsley leaves and tender stems