Preheat the oven to 350°F. Coat a 9x13 inch pan with cooking spray, olive oil or butter. Set aside.
In a large bowl, add the flour, baking powder, cinnamon and salt. Stir to combine.
In another bowl, add the egg yolks and 3/4 cup of sugar. Beat together on high speed using a handheld or stand mixer for about 3 minutes, until the yolks are pale yellow in color.
Add the vanilla extract and 1/2 cup of milk. Beat together on low until just combined and pour it into the large bowl of flour. Mix together with a fork until combined.
In another large bowl, add the egg whites and beat on high speed using a handheld or stand mixer until soft peaks form. With the mixer on, gradually add in the remaining 1/4 cup sugar and beat until egg whites are shiny and stiff.
Add the egg white mixture to the cake batter and fold them together very gently using a silicone spatula until just combined. You want to try to keep as much of the light airy texture and volume of the egg whites as possible, while making sure that the egg whites are completely combined with the batter.
Pour the cake batter into the prepared pan and bake for 35 to 40 minutes, or until a toothpick inserted into the center comes out clean. Set aside to cool for 10 minutes while you make the three milk mixture.
In a medium bowl, add the remaining 1/4 cup of milk, sweetened condensed milk and evaporated milk. Whisk together to combine.
Using a knife or a spatula, gently unstick the sides of the cake from the pan. Then, poke holes all over the cake using a toothpick, a skewer or a fork.
Gradually pour the three milk mixture over the cake. Cover and refrigerate for at least two hours to let the cake fully cool and absorb the liquid.
For the topping
In a large bowl, add the heavy cream, sugar and vanilla extract. Beat on high speed using a handheld or stand mixer until soft peaks form.
Top the cake with whipped cream and freshly sliced strawberries, if desired.
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Notes
*I like using clear vanilla extract because the color of the whipped cream stays super white and bright. However, if you don’t really care if the whipped topping is an off white color, you can use your regular pure vanilla extract instead.To make the sponge cake light and airy, the one important step is beating the egg whites until shiny peaks form, and then gently folding them into the cake batter. The air bubbles and volume of the meringue help keep the sponge fluffy and not dense, even after soaking in the three milk mixture.