In a small bowl pour condensed milk and add cornstarch. Mix until incorporated. Set aside.

In a sauce pan bring milk, cream, sugar, and vanilla bean just to the beginning of a boil. Stir to avoid scorching the milk.

Remove milk and sugar from heat and add your starch and condensed milk mixture. Stir vigorously until it thickens. Pour into a bowl and press plastic wrap directly onto the surface of your pastry cream. Make sure the plastic wrap touches as much of the surface of your cream as you can. Chill in fridge.

Once your cream is completely cold and thick, remove and de-seed the vanilla pod, adding the seeds into the cream. An optional step is to push the cold pastry cream through a fine mesh strainer to ensure no lumps. In a medium bowl mix the pastry cream on high for about 3 minutes or until soft. Pour a cup of heavy whipping cream into a separate bowl and whip until you can make stiff peaks in the whipped cream by pulling your whisk up. Add your whipped cream into your whipped pastry cream and gently fold together. You should have a fluffy white diplomat cream.

Take your first layer of cake and add a 2 to 2 ½ inch layer of diplomat cream. We want a layer of diplomat cream almost as thick as the cake layers themselves.

Stack second layer of cake on the diplomat cream.

On the top of your cake, frost just the top of your cake with the remaining diplomat cream. Just like a normal layer of frosting. Leave sides bare.

Set cake in fridge to chill.

Separate eggs yolks from whites with cold eggs until you get 400 grams of egg whites. After it is measured, leave the egg whites out in a covered bowl to reach room temperature.

Prepare two 9 inch round cake pans (or square) by lining them with parchment paper. Set aside.

Preheat oven to 320° F

Add milk, oil, and condensed milk to double boiler until mixture reaches 105° F.

In a bowl with the warmed oil and milk mixture, sift cake flour and milk powder. Mix until it forms smooth ribbons when you lift your whisk.

In a separate bowl whisk room temperature egg whites until foamy, then add ⅓ of your sugar.

Continue to whip your egg whites until foamy and opaque, then add another ⅓ of your sugar.

Whip until creamy and white, then add the remainder of your sugar and your room temperature lemon juice as well.

Whip until soft peaks form and sprinkle your cornstarch evenly across the top of your meringue.

Whip into stiff peaks.

Take ¼ of your meringue and mix it into your prepared cake batter until smooth ribbons form.

Gently fold cake batter into remaining meringue until fluffy and incorporated, making sure not to deflate your meringue.

Pour cake batter into prepared cake pans.

For the bain-marie, in a pan larger than your cake pans, pour boiling water 1 inch high. Set your cake pans in the bain-marie and bake for 25 to 35 minutes. Check the cake using the oven light. Keep the door closed. Cake is done when it springs back when touched.

Add heavy cream and sugar into a bowl. Whip until stiff peaks form.

Remove cake from the fridge and frost sides of cake with a generous layer of whip cream. Leave the diplomat cream on top of the cake uncovered.

Chill until ready to eat!