Preheat oven to 350 degrees. Line an 8 x 8 inch cake pan. Allow the paper to hang over the sides to use as "handles"
In a large mixer bowl sift or whisk together the dry ingredients until there are no lumps in the dry ingredients
Add the eggs. Beat on low to moisten the dry ingredients. Increase the speed to medium low and beat on medium low for 30 seconds or until fully combined
Scrape down the sides of the bowl. Add the butter. Beat on medium for 30 seconds or until fully combined and smooth
Scrape down the sides of the bowl Add the milk and the vanilla extract. Beat on medium for 30 seconds or until fully combined and a creamy batter has formed.
Scrape down the sides of the bowl. Push all the ingredients to the center of the bowl. Scrape the batter into the prepared cake pan. Use a spatula. wooden spoon or fingers to spread the batter evenly in a thin layer throughout the cake pan
Bake at 350 degrees for 20-25 minutes or until golden on the edges or until a tester comes out clean
Remove from the oven. The cake will be soft but will firm up as it cools. Allow to cool in pan 30 minutes or until firm enough to remove from the pan
Grasp the parchment paper "handles" carefully lift cake from pan and place on a wire rack. Place in the refrigerator and chill about 15 minutes so the cake will not crumble when being cut. The last few minutes before removing the cake begin the filling