Layer 1 (Cake) Crust Batter
Heat oven to 395°F (200°C).
In a large mixing bowl start mixing yolks with a hand mixer while adding the sugar to the bowl one tablespoon at a time. Mix 5-6 minutes on high, or until yolks turn light yellow and easily separate from bowl walls.
With a wooden spatula add flour, walnuts and chocolate to egg yolks. Stir everything until well integrated.
In a separate large mixing bowl beat egg whites and a pinch of salt with a hand mixer. Start by mixing on low for one minute, then finish off with 2-3 minutes on high or until firm peaks form.
With a wooden spatula add egg yolk mixture to egg whites. Mix in slowly but thoroughly so that at the end the batter feels light and airy.
Take a 9-10 inch (24cm) adjustable cake ring (pan) and line the bottom with parchment paper. Using a baking brush paint the ring walls and bottom generously with butter.
Pour batter into cake ring and shake lightly until batter is evenly distributed. Lower temperature to 355°F (180°C) and bake for 20 to 30 minutes. Use a toothpick to check for doneness.
Cool the cake off completely. Using a knife gently separate cake from ring walls. Open the ring and transfer the cake (crust face down) onto plate you’ll be serving it on. Carefully remove parchment paper from the cake.
Layer 2 Orange Infused Topping
In a small pot combine milk and sugar and bring to a boil on high. Lower the temperature and stir frequently until sugar dissolves in milk.
Melt chocolate with 2-3 tablespoons of milk on low at the same time. Stir frequently to prevent burning.
In a large mixing bowl cover walnuts evenly with sugar and milk. After walnuts absorb the liquid completely add melted chocolate, orange juice and zest. (If using, add rum or Grand marnier now also.) Mix well until integrated. Let cool.
Meanwhile make a bain marie (heated bath) by placing a pot filled with water one third of the way on the stove. Bring water to a boil, then lower temperature just enough to keep it at a slow boil.
(Parallel to water warming up) In a large metal mixing bowl (that can partially fit into the pot from the step above) start mixing yolks with a hand mixer while adding the sugar to the bowl one tablespoon at a time. Mix 3-4 minutes on high, then transfer the bowl into the pot. (There should be a little bit of space between the water and the bottom of the bowl, but the bowl should prohibit the steam from leaving the pot.) Keep stirring egg yolks quickly and continuously with a plastic spatula around 5 minutes. Remove egg yolks from steam heat and let cool.
In a large mixing bowl mix butter until soft with a hand mixer. Add egg yolks and continue mixing. Finally add the remaining mixture (walnuts, etc.) and mix a few more minutes until the layer is well integrated and airy (light) at the same time. Transfer to fridge for 45 minutes to 1 hour.
Combining layers 1 and 2: Place a (clean) cake ring (just the side portion) about half way up the cake crust and close it. Evenly distribute layer 2 on top of the cake crust. Use a knife if necessary. Transfer back to fridge leaving the cake ring on.
Layer 3 Italian Meringue
In a small pot bring water and sugar to a boil. Bring temperature to low and stir occasionally. Cook for 20-30 minutes, or until the syrup is of a consistency of thin honey.
About 5 minutes before syrup is finished in a large mixing bowl beat egg whites and a pinch of salt with a hand mixer. Start by mixing on low for one minute, then finish off with 2-3 minutes on high or until firm peaks form.
(Please note if you are wary of bacteria (salmonella) you can do this step using a bain marie like you did for layer 2 egg yolks. Fill a pot one third with water and bring to a boil on high. Water should be boiling by the time you’re ready to beat egg whites, or about 5 minutes before the syrup is done. The rest is the same by adding the syrup in while mixing on steam.)
Continue beating egg whites while lightly pouring the syrup into the bowl. You are now mixing until stiff peaks form. Syrup should be trickling in for about 5 minutes to give you enough time to mix it in. After you’ve mixed all the syrup turn the mixer off, and flip the bowl around. If the meringue stays in the bowl you’re finished. If it moves mix a little longer.
Combining layers 1 and 2 with layer 3. Take the cake out of the fridge and remove the cake ring. Wash and dry it, then place back on the cake (about half-way up) and close again. Pour meringue on top and evenly distribute as the third layer. As you’re distributing push lightly to avoid air being trapped inside. Return back to the fridge.
(Optional & Highly Recommended) Layer 4 Chocolate Glaze (Ganache)
After the meringue layer has completely cooled down, melt all glaze ingredients on low. Stir frequently to avoid burning. If it looks too thick, add a little more milk. (Meringue has to be completely, 100% cool.)
Transfer to a strong plastic bag, cutting off a very small tip on one end. Pour chocolate first on meringue edges so that chocolate drips down the sides of all of the cake’s layers for a beautiful visual effect. Pour remaining chocolate on top and use a dull edge of a long knife to even it out.
Return to the fridge. Leave overnight at the very least. (Best if you can wait an entire day before you eat it.)
The cake lasts up to 7 days in the fridge.