Gather all ingredients. Preheat the oven to 325 degrees F (165 degrees C). Grease and line two 9-inch round cake pans with parchment paper.

Sift flour, baking powder, and salt together in a bowl.

Separate the eggs and set egg whites aside. Beat egg yolks together on medium-high speed until very thick, about 4 minutes. Gradually add 1/2 cup of cold water. Add 1 1/4 cups of white sugar, slowly, and beat well for about 3 more minutes. Add 1 teaspoon of vanilla. Add flour mixture to egg yolk mixture and fold in.

Beat egg whites and cream of tartar together until stiff peaks form. Fold into egg yolk mixture; divide the cake batter between the prepared pans.

Bake cakes in the preheated oven for 25 minutes. Cool on wire rack for 10 minutes; invert and cool completely. While the cakes are cooling, you can make the ricotta filling and rum syrup.

To make the ricotta filling: Beat ricotta cheese well and add confectioner's sugar and cinnamon. Add 1 1/2 teaspoons of vanilla and 2 ounces of grated chocolate. Stir in candied lemon peel and mix. Chill filling until ready to use.

To make the rum syrup: Place 1/3 cup of sugar and 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 rum. Cool syrup to room temperature.

Cut each cooled cake in half. Place one of the 4 halves on a cake board or plate and sprinkle with a little of the rum syrup.

Spread 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 remaining piece of cake. Chill cake in the refrigerator for at least 4 hours.

To make the chocolate glaze: Melt 6 ounces of chocolate and cream together in a microwave-safe bowl in the microwave; whisk until smooth. Add butter and whisk until dissolved. Cool mixture until spreadable.

Spread over the top of the chilled cake.