In a medium bowl hand whisk together flour, cocoa powder, baking powder, and salt. Set aside.
In bowl of stand mixer fitted with paddle attachment, cream together room temperature butter, brown sugar, and granulated sugar.
Add SunButter, vanilla, and oil. Mix on medium low until creamy. Scrape bottom and sides of bowl as needed.
Add each egg one at a time until incorporated.
Pour in milk and water. Mix until incorporated.
Slowly spoon in flour mixture, scraping bottom and sides of bowl as needed until cake batter is formed.
Divide batter equally amongst the three cake pans and bake for 30-35 minutes until toothpick inserted into center comes out with just soft crumbs.
Place cake pans on cooling rack until completely cooled.
Remove cake layers from pans, wrap in plastic wrap and freeze for 30 minutes.