Pre-heat the oven to 350ºF.

Prepare a 9x13” cake pan by greasing it with butter, or with oil spray.

In a small bowl, whisk together the flour, baking powder, and salt. Set aside.

Separate the egg whites from the egg yolks. Place the whites in a large bowl or in the bowl of a mixer.

Add the yolks to another large bowl.

Mix 3/4 of the sugar in with the yolks and whisk by hand, or you can either use a stand mixer or a hand mixer. You should whisk until the yolk and sugar mixture is pale in color, fluffy, with a foam consistency, and falling off the whisk in ribbons, which can take a couple of minutes of whisking with a mixer, and 3 or 4 whisking by hand. This is called the ribbon stage and it refers to the flow of the mixture falling from the whisk.

Add the milk and vanilla extract to the bowl and mix. Add the flour mixture and mix until combined.

Set this batter aside.

In the other large bowl, whip the egg whites with the remaining 1/4 cup of sugar using an electric mixer on medium high speed until the mixture achieves stiff peaks, which should take 2 to 4 minutes. If you flip the bowl over, the whites shouldn’t move or slide, they should be firm and stiff. That’s when you know they’re ready.

Add half of the meringue you just whipped to the batter containing the yolk mixture. Fold with a spatula until incorporated.

Add the remaining meringue to the bowl and fold until you obtain a smooth batter.

The batter should be very fluffy and light.

Pour it on the prepared pan.

Use a spatula to smooth the batter out evenly.

Bake in the pre-heated oven for 30 to 35 minutes, until a toothpick comes out clean once inserted in the cake.

When you remove the cake from the oven, I like to run a spatula around the edges of the pan to let the cake loose, this way it won’t break as it cools down, because the cake will shrink once you remove it from the oven.

Let it cool down at least 30 minutes.

Prick the top of the cake with a fork.

In a large spouted measuring cup or bowl, add the evaporated milk, sweetened condensed milk, and heavy cream. Whisk to combine fully.

Pour the milk mixture all over the cake.

Cover the pan with plastic wrap. Place it in the fridge for at least a few hours. I like to leave it overnight.

Place the heavy whipping cream and powdered sugar in a bowl of a stand mixer, or use a hand mixer to whip the mixture for about 4 minutes on medium speed, or until soft peaks form.

Add the vanilla and mix to combine.

Pour the whipped cream over the cake, spread it with a spatula. Or you can use a piping bag to pipe the whipped cream.

Sprinkle the cinnamon on top, I find it best to use a small sifter to do this.

Another option instead of the whipped topping for the Tres Leches Cake, you can make a toasted meringue frosting. I like to make it using the Swiss method.

Fill a small pot with 2 inches of water. Place it over medium heat. Bring to a gentle simmer.

Add the egg whites, sugar, cream of tartar, and salt to a large glass bowl, and whisk to combine.

Place the glass bowl on top of the pan to form a double boiler.

Continue to whisk the mixture over the double boiler, until it reaches 140ºF, or until the mixture is just barely hot, and the sugar has entirely melted.

Remove from the double boiler. Either whip the mixture in the bowl it already is using a hand mixer, or transfer the syrup to the bowl of a stand mixer, and whip using the whisk attachment.

You should whip the syrup for about 10 to 15 minutes, or until stiff peaks form. The mixture should be thick, elastic, glossy, forming stiff peaks.

Add the vanilla and mix to combine.

Store the Tres Leches Cake in a container in the fridge for up to 4 days.