Preheat your oven to 350 degrees. This ensures that your cake will bake evenly and rise perfectly.
In a large bowl, sift together the all-purpose flour, baking powder, and salt. Sifting helps to aerate the flour and removes any lumps, creating a smoother batter.
In another bowl, combine the eggs and sugar. Using a stand mixer with a whisk attachment, mix on high speed for 10 to 12 minutes, or until the mixture is light and fluffy. You want it to double in size and turn a pale yellow.
While mixing on high speed, slowly pour in the vegetable oil and continue mixing until well combined.
Remove the mixing bowl from the mixer and gently fold in the sifted dry ingredients in two batches using a rubber spatula. Be careful not to overmix; you just want everything combined.
Transfer the batter to a greased 13x9 casserole dish, spreading it evenly. Bake for 35 to 40 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean.
Once baked, allow the pan to cool completely to room temperature. This is essential because you want to add the milk mixture without it being too hot.
Meanwhile, in a separate large bowl, whisk together the evaporated milk, condensed milk, and heavy whipping cream until fully combined. This rich mixture will soak into the cake.
Once the cake has cooled, use a fork to pierce it all over, allowing the soaking mixture to penetrate the cake deeply. Pour the milk mixture evenly over the cake and let it sit until fully absorbed, which usually takes about an hour.
Top the cake with whipped cream and spread it evenly. For an optional garnish, dust the top with cinnamon and cocoa powder, and serve with fresh berries.