Cocoanut Filling

This is an uncooked meringue-style frosting: raw egg white beaten with powdered sugar, never heated at any stage. That single fact governs everything below.

• The eggs are never cookedThe whites are beaten on a platter and spread straight onto a finished cake. Nothing in the method brings them near the 160F at which Salmonella in egg white is reliably killed, and a sugar-and-egg frosting sitting at room temperature on a layer cake is a growth medium rather than a preservative. A current recipe using pasteurised whites or a cooked syrup method should be used instead.
• Why 1900 was less worriedWhy the period was less worried -- Eggs in this era were generally used closer to laying and stored in a cool larder, though how far that held in any given household is not documented. Modern distribution, longer shelf life and the documented rise of egg-associated Salmonella enteritidis in the twentieth century changed the calculation.
• "Cocoanut" means fresh coconutThe older spelling is the same nut. The recipe calls for it freshly grated from the shell, which is moist and sweet-tasting; packaged sweetened shredded coconut is much drier and considerably sweeter, and unsweetened desiccated coconut drier still.
• Powdered sugarThen as now this is finely ground sugar, but period powdered sugar generally lacked the anti-caking starch of modern confectioners' sugar, which stiffens a frosting slightly faster.
• No quantities givenSugar and coconut are both left to judgement: 'enough to spread' and 'sprinkle thickly.' The recipe gives no yield either, though it does direct that the filling go between the layers and on top.
• Beating on a platterBeating whites on a flat platter with a fork is an older hand method; a wide shallow surface lets a fork drag air through a thin film of white. The recipe itself gives no reason for specifying a platter rather than a bowl.