Preheat oven to 350°F
Add the sugar and coconut oil to a mixer fitted with a paddle attachment. Beat on medium until well combined. Slowly add the oil and vanilla, beating on high until the mixture resembles frosting.
Add the baking soda and vinegar, beat again until well combined.
Stir in the beer.
In a mixing bowl stir together the cocoa powder, flour, cornstarch, salt, and espresso powder.
Gently stir the dry ingredients into the wet ingredients until just combined, mixture will be thick.
Add in an even layer to a greased 8x8 pan, press flat.
Bake for 22 minutes. Allow to cool before cutting into squares.