Whisk the egg whites in a stand mixer until you get soft peaks. Gradually add the sugar whilst you continue to beat the egg whites until the mixture is glossy and you get stiff peaks. If the mixture is rubbed between your fingers there should be no sugar crystals - if the mixture still feels gritty keep beating it until smooth, then finally beat in the vanilla extract.
Spread the mixture out on two lined cookie sheets to form four, 6-inch diameter disks (see notes). Bake for one and a half hours in an oven preheated to 250 F (120 C) then switch the oven off and leave the meringue in the oven for a further hour.
Melt the chocolate and stir in 1/4 cup of the cream.
Whisk the rest of the cream until just thickened.
To assemble: take one meringue disk and spread a quarter of the chocolate mixture over it. Spread a quarter of the cream over this and then scatter over the cherries. Top with the next meringue stack and repeat the chocolate, cream and cherry layering until you've stacked up all the meringues. Grate a little extra chocolate over the cake for a finishing touch.
Serve immediately or freeze for an hour before slicing for a cleaner cut (see notes).