Preheat the oven to 375. Grease an 8-inch cake pan with oil and line the bottom of it with baking paper.
Put the nut milk and cocoa powder in a medium bowl and whisk to combine. Add the coconut sugar, almond flour, flour, baking soda and salt and whisk until combined.
Add the avocado oil and cider vinegar and whisk until the batter is thick and smooth but pretty runny.
Pour the batter into the cake pan. Sprinkle the chocolate chunks over the cake and bake for about 20 - 25 minutes or until a tooth pick inserted into the center comes out clean.
Let the cake cool completely on a wire rack before you invert it, about 10-15 minutes or so.
Run a knife around the edge of the cake, invert onto a serving plate or cake stand.