Preheat oven to 350 degrees.
Grease an 8x8 inch pan with vegetable oil or olive oil.
In a large bowl, combine two sticks room temperature unsalted butter and two cups of sugar.
With an electric hand mixer at medium speed, mix the batter for about two to three minutes. Mix until well combined and there are no lumps, making stiff peaks.
Then, mix in four eggs and one half a cup of warm water. Continue to blend well.
Add in two cups of All-purpose flour, one tablespoon baking powder and one-half teaspoon vanilla extract. Blend well.
Pour all of the cake batter into a greased 8x8 inch pan.
With a spoon or a rubber spatula, smooth batter evenly.
Put your pan into the preheated oven for approximately forty minutes. Checking it every ten minutes or so.
When completed baking, let cake set in pan for ten minutes out of the oven.
Then transfer it carefully onto a wire rack to finish cooling.
Cut into individual pieces and store in an airtight container.