Preheat oven to 350°F (175°C). Lightly grease a 9-inch round cake pan (or line with parchment) and dust with a little gluten-free flour or use a removable parchment round.

Combine dry ingredients

In a large mixing bowl whisk together oat flour, almond flour, baking powder, baking soda, and salt until evenly combined and aerated.

Combine wet ingredients

In a separate bowl combine the thickened flax egg, applesauce, almond milk, melted coconut oil, vanilla, and maple syrup. Whisk until smooth and slightly frothy.

Mix batter

Pour the wet mixture into the dry ingredients. Stir with a spatula or whisk until just combined. Do not overmix. Scrape the sides and bottom to incorporate any dry pockets.

Adjust consistency

Batter should be thick but pourable. If too thick, add up to 2 tablespoons additional almond milk. If making chocolate cake, fold the cocoa powder in now and whisk until uniform.

Add mix-ins

Fold in any optional mix-ins (berries, nuts, or coconut) gently to avoid breaking berries.

Bake

Transfer batter to the prepared pan and smooth the top. Bake in the preheated oven 28–35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs (especially for gluten-free cakes). Rotate the pan halfway through baking for even browning.

Cool

Remove cake from oven and set on a wire rack. Let cool in the pan 10–15 minutes, then run a knife around the edge and invert onto the rack or leave in pan to cool completely before frosting. Cooling completely prevents frosting from melting.

Optional Frosting & Toppings

Prepare frosting

For a simple sugar-free vegan frosting, whip vegan cream cheese and coconut cream in a chilled bowl until smooth. Add vanilla or lemon zest to taste and a tablespoon of powdered erythritol or a few drops of liquid sweetener if desired (optional). Chill 10 minutes to firm up if too soft.

Assemble

Once cake is completely cool, spread frosting evenly over the top (and sides if using a layer cake). Sprinkle with shredded coconut, chopped nuts, or arrange fresh berries on top.

Store

Store cake covered in the refrigerator for up to 4–5 days. Bring to room temperature 20–30 minutes before serving for best texture. You can freeze individual slices wrapped tightly for up to 2 months; thaw overnight in the fridge.