Preheat the oven to 325 degrees fahrenheit. Spray a 9x13 baking dish with cooking spray and set aside.

Add the eggs and sugar to a large bowl and beat with the whisk attachment on a stand mixer or a hand mixer for 4-5 minutes, until very pale in color and tripled in volume.

Add the flour, baking powder, and salt to a small bowl and whisk to combine.

Add the butter to a small saucepan. Heat over medium until melted and then add the milk and vanilla. Continue to heat until just barely steaming.

Remove the butter mixture from the heat, turn the mixer on low and very slowly pour the butter/milk mixture into the eggs while beating.

Once fully incorporated, add the dry ingredients to the batter in two additions, mixing on low until just combined.

Pour the batter into the prepared pan. Bake for 40-45 minutes, until a toothpick comes out of the center of the cake clean.

Let the cake cool for 10-15 minutes before serving. Top with a dusting of powdered sugar and serve with whipped cream and berries, if desired.