Preheat the oven to 350℉ & grease & parchment line a 9" x 9" cake pan
In a large mixing bowl combine the flour, sugar(s), salt, baking powder & baking soda & whisk to combine evenly
Combine the flax meal with the hot water & let stand for 5 minutes to thicken
Combine the hot brewed coffee with the cocoa powder & whisk smooth.
Now pour the coffee/cocoa mixture along with the applesauce, flax paste & vanilla extract into the dry ingredients & whisk to a smooth batter
Pour the batter into the prepared pan & bake for approximately 30 minutes or when it is springy to the touch when you gently press the center or do the toothpick test for moist crumbs not raw batter
Cool the cake in the pan until you can safely touch it without burning your fingers them flip it out onto a cooling rack remove the parchment paper then revert back to the other side to avoid cracking since this cake has a slight dome *see notes for more!
While the cake is cooling prepare the buttercream & ganache recipes according to the instructions on those pages.
Once the cake is cold trim off the domed top (reserve for another recipe in the freezer! You never know when you will need cake crumbs!)
Pipe the buttercream in wide strips from once end of the cake to the other
Pour the ganache over top then trim off any messy edges to reveal the bumpy cake pattern on each slice