Preheat oven to 350 degrees F. Place cake pan on a parchment paper, circle with a pen and cut out a round. Grease bottom and sides of the pan with butter or coconut oil really well. Place round inside the cake pan and grease it too.
In a large bowl, add eggs and whisk well. Add maple syrup, vanilla extract, baking soda, and salt; whisk until well combined.
Add cacao powder and whisk well until all incorporated and no lumps. Add almond flour and mix with spatula until well combined.
Pour batter into previously prepared cake pan and bake on the middle rack for 23-25 minutes or until a toothpick inserted in the center comes out clean.
Remove from the oven and let cool in a pan for an hour or so. Using a flat spatula carefully separate edges of the cake from a pan and transfer to a cooling rack.
Sprinkle with icing sugar, cut into 10 slices and enjoy.
Notes
Store: Refrigerate covered for up to 3-4 days.
Freeze: You can freeze cake tightly wrapped in a few layers of plastic wrap for up to 3 months. Thaw on a counter for a few hours.
Sweetener: Other liquid sweeteners will work but the flavor will vary. Dry sweetener might work but I haven't tested.
Almond flour: Use superfine blanched almond flour. If you use almond meal, then the texture will be more dense.
Do not use springform pan: Because it deforms the shape of cake and makes it very thin looking.
Make sure to use the spoon and level method: When measuring the almond flour (rather than scooping the cup directly into the flour bag).