Frozen Brazo de Mercedes Cake

From 6 Bittersweets (Guest Post by Trissalicious)
Serves 10 to 12

Meringue Layer
8 egg whites [save yolks for custard layer]
1/2 cup (110 grams) sugar
pinch of cream of tartar or egg white powder

Preheat the oven to 275 F (135 C) for non-convection ovens OR 250 F (120 C) for convection ovens. Grease and line a 15 x 10-inch pan and then grease the baking paper once more. Using a stand mixer, beat the egg whites until semi-stiff peaks and then gradually start adding the sugar until you have stiff peaks but make sure that you don't over beat the egg whites, otherwise it will go grainy. Spread the egg whites on to the baking tray and bake for 40 minutes. Remove from the heat and then place the baking tray on top of a rack and allow to cool. Set aside.

Custard Layer
8 egg yolks
10.58 oz. (300 grams) sweetened condensed milk
3 tablespoons (around 50 grams) of butter

Place the egg yolks and condensed milk in a stainless steel bowl and place the bowl a top a pot of simmering water, making sure that the water does not touch the bottom of the bowl. Mix the egg yolks and the condensed milk until thick using a whisk until the mixture has thickened like a custard. Remove from the heat and then add the butter, making sure to fully incorporate. Allow to cool in the refrigerator and set aside until needed.

Graham Crust
8.8 oz (250 grams) graham crackers OR digestive-style biscuits, crushed using a food processor
2 tablespoons sugar
3 tablespoons (around 50 grams) of butter

Preheat the oven to 350 F (175 C) for non-convection ovens OR 320 F (180 C) for convection ovens .

Heat the butter in the microwave until melted, then add the sugar and the graham crackers. Mix thoroughly and then spread over two 8 1/2 x 6-inch pans. Bake for 10 minutes and then remove. Allow to cool before assembly.

Assembly
4 1/4 cups (1 liter) vanilla ice cream, softened at room temperature for about 10 minutes

To assemble, place a layer of ice cream, around half an inch (1.3 cm or so) thick, over the graham crust. Place the mixture in the freezer and allow to set for around 30 minutes. Then add the custard layer and then return this to the freezer and allow to set for another 30 minutes. Finally, cut the meringue (you will have more than you need, so ensure that you can cut it large enough to fit the tray) to fit the two trays and place on top of the custard layer. Return the dessert to the freezer and allow to set for around three hours.