Preheat the oven to 350°F (175°C). Grease a 9x13-inch glass or ceramic baking dish.
In a medium bowl, whisk together the flour, baking powder, salt, and cinnamon.
In a large mixing bowl, beat the egg yolks with ¾ cup of sugar until pale yellow and thick, about 2 minutes. Stir in the vanilla extract, coconut extract, and milk.
Gently mix in the dry ingredients until just combined.
In a separate bowl, beat the egg whites until soft peaks form. Slowly add the remaining ¼ cup of sugar and beat until stiff peaks form.
Gently fold the egg whites into the cake batter in three additions, keeping as much air in the batter as possible.
Pour the batter into the prepared pan and bake for 25 to 30 minutes, or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely.
Soak the Cake:
In a large measuring cup or mixing bowl, whisk together the evaporated milk, sweetened condensed milk, heavy cream, cinnamon (if using), and vanilla extract.
Once the cake is cool, use a fork or skewer to poke holes all over the surface.
Slowly pour the milk mixture evenly over the cake. Cover and refrigerate for at least 4 hours or overnight.
Make the Whipped Topping:
In a mixing bowl or food processor, combine the chilled heavy cream, powdered sugar, vanilla extract, and nonfat dry milk powder.
Whip the cream until stiff peaks form. Stop and check frequently to avoid overwhipping.
Spread the whipped topping evenly over the soaked cake just before serving.
Notes
Erren’s Top Tips
Let the cake cool completely before adding the milk or it won’t absorb properly and can turn dense.Pour the milk mixture slowly in stages instead of all at once. This helps even absorption and prevents soggy spots.Use a fork or skewer to poke plenty of holes. More holes means better distribution of the soak.Stop whipping the cream as soon as it holds its shape. Overwhipped cream will look grainy and won’t spread smoothly.For clean slices, chill the cake overnight and wipe your knife between cuts.
Variations & Add-Ins
Coconut Tres Leches Replace part of the heavy cream in the soak with coconut milk and increase the coconut extract slightly.Strawberry Topped Version Add sliced strawberries between the cake and whipped topping or pile them on top just before serving.Coffee-Infused Twist Add a teaspoon of instant espresso powder to the milk mixture for a subtle mocha depth.Rum-Spiked Version Add a tablespoon of dark rum to the milk soak for a deeper, slightly caramelized flavor.
Storage & Freezing
Store covered in the refrigerator for up to 3 days. The texture actually improves after the first day.For best results, add the whipped topping the day you plan to serve.Freezing is not recommended once soaked, as the texture can become watery when thawed. You can freeze the baked sponge before soaking if needed.