Preheat the oven to 350°F (175°C) and grease a 9x13-inch baking pan; line with parchment if you prefer easy removal.
In a large bowl, beat the Eggs with the Granulated Sugar until pale and slightly thickened, about 3–5 minutes. Stir in the Vanilla Extract.
Sift together the All-Purpose Flour, Baking Powder and Salt and gently fold into the egg mixture. Gradually add the Whole Milk and fold just until the batter is smooth and homogenous.
Pour the batter into the prepared pan and bake for 25–30 minutes, or until the top is golden and a toothpick comes out with a few moist crumbs. Let the cake cool in the pan for 10–15 minutes.
While the cake is cooling, whisk together the Sweetened Condensed Milk, Evaporated Milk and additional whole milk to create the tres leches mixture; stir in a little more vanilla (if you like) for extra flavor.
Using a fork or skewer, poke holes all over the warm cake, then slowly pour the milk mixture evenly over the surface so it soaks into the sponge. Cover and refrigerate for at least 2 hours, preferably overnight, to fully absorb.
Just before serving, whip the Heavy Cream with the Powdered Sugar and a splash of Vanilla Extract until soft to medium peaks form. Spread the whipped cream evenly over the chilled soaked cake.
Dust the top lightly with Ground Cinnamon for aroma and color, slice into squares, and serve chilled. Enjoy!
