Preheat the oven to 165 degrees C (325 degrees F). Grease and line with parchment paper 2 24cm round layer pans.
Sift the flour, baking powder, and salt together.
Separate the eggs and set the egg whites aside. Beat the egg yolks together on medium-high speed until very thick, about 4 minutes. Gradually add the cold water. Add 1- 1/4 cups of the caster sugar, slowly, and beat well for about 3 more minutes. Add 1 teaspoon of the vanilla. Sift the flour mixture over the egg yolk mixture and fold in.
Beat the egg whites and cream of tartar together until stiff peaks form. Fold this into the yolk mixture. Divide batter between the pans.
Bake at 165 degrees C (325 degrees F) for 25 minutes. Cool on rack for 10 minutes and then invert and cool completely.
Cut each cake layer in half. Place one of the 4 halves on a cake board or plate and sprinkle with a little of the Rum Syrup. Spread about 1-1/2 cups of the Filling over this layer. Add a second layer of cake and repeat this procedure. Top the cake with the last layer of cake. Chill at least 4 hours. Spread Chocolate Glaze over top of cake.
To Make Ricotta Cheese Filling: Beat the ricotta cheese well and add the icing sugar and cinnamon. Add 1-1/2 teaspoons of the vanilla and grate 60g of the chocolate in using the coarse side of a grater. Stir in the candied lemon peel and mix. Chill until ready to use.
To Make The Rum Syrup: Place 1/3 cup of the sugar and the water in a small saucepan. Bring to a boil over medium heat, stirring to dissolve sugar. Boil 1 minute and then remove from heat and add the rum. Cool to room temperature.
To Make The Chocolate Glaze: Melt 180g of the chocolate and the cream in the microwave, whisk smooth. Add the butter and whisk until dissolved. Cool mixture until spreadable. Spread over the top of the cake.