Grease an 8-inch (20-cm) pan.
Preheat oven to 375°F (190°C).
To make cake, beat eggs, sugar, salt and cinnamon until thick.
Sift flour, baking powder and cocoa; fold into mixture with almonds and rum.
Turn batter into greased pan.
Bake 35 to 40 minutes or until a wooden pick inserted in center comes out clean.
Cool on a rack.
Cut cooled cake into 3 layers.
To make filling and topping, blend cornstarch, cocoa powder, sugar, egg yolks and a little milk.
Bring remaining milk to a boil.
Stir milk into cornstarch mixture.
Return to heat and stir until boiling.
Cool, stirring frequently.
Beat butter until soft.
Gradually beat cornstarch sauce, liqueur and chocolate into butter.
Join layers with chocolate cream and spread thinly over top and sides.
Decorate with rosettes, cherries and chocolate curls.