Melt over low heat 2 tablespoons butter. Add and blend in 2 1/2 tablespoons flour. Stir in slowly 1 1/2 cups hot milk. Season with 1/4 teaspoon salt and 1/2 teaspoon paprika. Stir until thickened and add 1 package imitation crab and bring to a boil. Then add 3 tablespoons sherry. Serve in patty shells or on toast. Serves 4.