Preheat the oven to 350°F / 175°C. Grease a 9 × 13in / 23 × 33cm baking pan. Mix 1½ cups of all-purpose flour, 1 tablespoon of baking powder, ¼ teaspoon of cinnamon, and ⅛ teaspoon of salt.
Measure 1 cup of sugar and 1 cup of whole milk. Separate 5 large eggs. Beat the yolks with three-quarters of the sugar until pale. Mix in 2 teaspoons of vanilla extract and half the milk, then the flour mixture.
Beat the whites with the remaining sugar to stiff peaks. Gently fold into the batter, pour into the pan and bake for 30-35 minutes, until a skewer comes out clean.
Cool completely, then poke holes all over with a skewer. Mix the remaining milk with 397g of sweetened condensed milk and 354ml of evaporated milk. Slowly pour over the cake.
Cover and refrigerate for at least 2 hours.
Whip 473ml of heavy cream, 3 tablespoons of sugar, and ½ teaspoon of vanilla extract to stiff peaks. Spread over the cake and serve chilled.
