Spray an 8x8 pan then line with parchment paper. Scrunching up the parchment into a ball and then flattening it makes it easy for it to stay in place and to shape it into the pan.
In a large bowl, add flour, cocoa powder, sugar, and salt. Whisk well to combine.
Add in oil, eggs, and vanilla.
Mix until just incorporated then mix for 50 strokes. The batter should be dense, smooth, and shiny. You can use a whisk or spatula to mix.
Spread batter into prepared pan then tap pan once or twice to allow air bubbles to escape.
Bake for 40 - 45 minutes. Test with a toothpick halfway between the edge and center of pan. There should be a few crumbs attached, but it should not be gooey.
Allow to cool completely for a clean cut. Cut into any size bars you like. Enjoy.
Notes
* I like to change it up by substituting bourbon, coffee brandy, or Frangelico for the vanilla. It gives such a delicious flavor. The alcohol cooks off and it's such a small amount. Remember, vanilla is made with vodka so using any of these is no different.