Preheat oven to 180°C and grease three 18cm tins.
Sift flour, cocoa, and bicarbonate of soda into a bowl with salt.
Cream butter and sugar, then mix in egg yolks, beetroot, and vanilla.
Stir in half the flour, followed by hot water and remaining flour.
Fold in stiffly beaten egg whites and divide between the tins.
Bake for 25-30 minutes and cool on wire racks.
Whisk mascarpone, icing sugar, and cream until thick and refrigerate.
Boil pitted cherries with Kirsch and sugar for 10 minutes.
Prepare truffles by melting chocolate into hot cream and cooling.
Roll chilled chocolate mixture into balls and refrigerate.
Whisk egg whites and cream of tartar to stiff peaks.
Boil sugar and water to 115°C, then slowly whisk into egg whites.
Stack cakes with jam syrup, mascarpone cream, and cherries.
Cover cake with meringue, brown with a torch, and garnish with cherries and truffles.