Heat oven to 350°F. Grease an 8 x 8-inch or9 x 9-inch baking dish with cooking spray. Set aside.
In a small mixing bowl, whisk together1/2 cup cane sugar, brown sugar and1/4 cupcocoa until evenly combined. Set aside.
In a medium mixing bowl, stir together 1/2 cupcane sugar, flour,1/4 cup unsweetened cocoa powder, baking powder and salt until evenly combined. Add in milk, avocado and vanilla, and stir until smooth. Spread the batter the prepared baking pan.
Sprinkle the initial sugar-cocoa mixture evenly over batter. Pour hot coffee (or water) evenly over the top of the sugar-cocoa layer. Do not stir.
Bake for 35 minutes. Remove from oven, and let cool on a wire backing rack for 15 minutes.
Serve immediately while the cake is warm, spooning the hot fudge mixture on the bottom of the pan over the cake.