In a small bowl, whisk together oat flour, baking powder cacao powder and salt.
Experts and novices agree that adding coffee to chocolate enhances chocolate flavor. I could find no article that credits anyone with the idea to do so. Perhaps is because coffee and chocolate hit European shores at roughly the same time (mid-1600's) and became rapidly popular? I did find one reference, however. Apparently in 16th century Venice chocolate was mixed with coffee and called bavareisa and became immensely popular. The rest is history