Preheat oven to 325 degrees. Grease and flour a 9x13" pan; set aside.
In a medium bowl, whisk together flour and next four ingredients. Set aside.
Place stick of butter and whole milk in a small sauce pan and heat over medium-low heat until butter in melted, stirring often. Remove pan from heat.
In the bowl of an electric stand mixture outfitted with a whisk attachment, beat the eggs until they are totally incorporated. Slowly add the 2 cups sugar, and beat on medium-high speed until the mixture is thickened and lightened in color, approximately 4-5 minutes. Stir in the hot melted butter mixture and the vanilla. Replace the whisk attachment with the paddle attachment. Add the flour mixture to the bowl in three additions, stirring well after each addition, scraping down the sides of the bowl with a spatula. Pour batter into prepared pan. Bake for 35 minutes, or until a cake tester in the center comes out clean. Remove from oven and cool slightly.
Using a wooden skewer, poke holes in the top of the cooked cake that are about 1/2 inch apart. Slowly pour the evaporated milk mixture over the top of the cake, making sure it is evenly distributed. Cover the pan with plastic wrap and chill for at least 3 hours.
Before serving, whip the 1 cup heavy cream, corn syrup and vanilla until soft peaks form. Spread the topping over the cake.
Serve chilled, and topped with fresh sliced berries, if desired.