This gorgeous tres leches cake is made completely from scratch. It's moist, decadent, and delicious, and it's the perfect centerpiece for any celebration that calls for cake.
Separate eggs; allow egg whites and yolks to stand at room temperature 30 minutes. Meanwhile, in a very large bowl combine flour, baking powder, and salt; set aside.
Preheat oven to 350°F. In a large bowl beat the egg yolks and granulated sugar with a mixer on high until yolks are pale yellow and doubled in size, about 3 minutes. Add whole milk and vanilla; beat 1 minute more. Pour yolk mixture over flour mixture; fold together with a rubber spatula until combined.
Thoroughly wash and dry the large bowl and beaters. Beat egg whites in the bowl on medium until soft peaks form (tips curl when beaters are lifted). Gradually add brown sugar and continue beating until stiff peaks form (tips stand straight). Gently fold egg whites into the yolk mixture just until combined. Spread batter into a greased 3-qt. rectangular baking dish.
Bake 20 to 25 minutes or until a toothpick comes out clean. Cool in baking dish on a wire rack.
Meanwhile, in a medium saucepan combine the sweetened condensed milk, evaporated milk, 1/2 cup of the heavy cream, and the cinnamon sticks (if using). Bring just to boiling over medium-high. Reduce heat and simmer gently, uncovered, 15 to 20 minutes or until reduced to 3 cups, stirring constantly. Remove from heat. If the pan doesn't have a pour spout, transfer the mixture to a 4-cup measuring cup or small pitcher.
Using a paring knife or skewer, pierce the cake all over. Slowly pour half the milk mixture evenly over the cake, going all the way to the edges. Wait 1 minute, then repeat with remaining milk mixture. Let cake cool to room temperature, then chill, covered, 8 to 24 hours.
To serve, beat the remaining 1 1/2 cups heavy cream and the powdered sugar with mixer on medium to high until stiff peaks form. Spread whipped cream over cake. If desired, top with strawberries.