oven baking: preheat oven to 350℉. Grease a 9inch square pan. Set aside.
air fryer baking: preheat oven to 340℉. Grease a 9inch square pan. Set aside.
In a large bowl, whisk together the flour, sugar, cocoa powder, instant coffee, baking soda, baking powder, and salt.
In another bowl (or measuring jug), combine the oil, almond or oat milk, hot water, prepared chia eggs, and vanilla extract. Pour the wet mixture into the dry ingredients and whisk until smooth.
Scrape the batter into the square pan and bake for 30-35 minutes, or until an inserted toothpick comes out clean. Remove from the oven and let it cool completely.