Tiramisu Sheet Cake Recipe

Preheat the oven to 350F (177C) convection (325F/163C conventional) and grease and line a 9x13" or a 10" square pan with baking spray and parchment paper.
Place the egg whites in the bowl of the stand mixer and using the whisk attachment, at full speed, beat until they're frothy.
6 large eggs 55-60 grams each, separated
With the mixer on medium speed, stream in the sugar. Turn the mixer up to full speed and beat just until the meringue reaches stiff peaks.
150 grams (3/4 cups) granulated sugar
Pour in the egg yolks and vanilla and turn the mixer to medium-high speed, mixing, a few seconds, just until they're fully combined.
1 teaspoon vanilla extract
Sift in the flour and salt (and baking powder if using) and turn the mixer up to medium-low speed, mixing just until the flour is incorporated.
120 grams (1 cup) all-purpose flour spooned and leveled, 1/2 teaspoon fine sea salt, 1 tsp baking powder read blog post
Scrape the edge of the bowl well and spread the batter evenly into the prepared pan. Bake for about 15-20ish minutes, until the cake is golden and separates itself from the edge of the pan. It will also spring back when you press on it gently.
Allow the cake to cool completely and then use a fork to poke holes all over it.

Stir the coffee with the sugar until the sugar is dissolved.
25 grams (2 Tbsp) granulated sugar, 240 mL (1 cup) strong coffee (I used 4 shots espresso and added 1/2 cup cold brew to make 1 cup)
Use a pastry brush or a spoon to drizzle the coffee onto the cake, try to get it as evenly as possible.

Place the cold mascarpone into the bowl of a stand mixer (or just a large bowl with a hand mixer) with the powdered sugar and salt.
8 ounces (1 small tub) mascarpone cheese, cold (I recommend Belgioioso)***, 120 grams (1 cup) powdered sugar, tiny pinch of fine sea salt
Beat at low-medium speed until they're combined and then increase the speed to medium-high for 1-2 minutes, scraping the edge of the bowl halfway through.
Add the vanilla and the cold heavy whipping cream in 3-4 increments, mixing well between each addition.
240 mL (1 cup) heavy whipping cream cold, 1 teaspoon vanilla bean paste
After adding all the heavy whipping cream, the cream may look soft, turn the mixer up to full speed for 1-2 more minutes and it should stiffen up (like whipped cream does).

Spread or pipe the mascarpone cream on top of the coffee soaked cake and dust with a generous amount of unsweetened cocoa powder.
Cocoa powder for dusting I used dutch
Refrigerate the cake for 1-2 hours to set, before serving.