Preheat your oven to 350 °F (177 °C). Grease and line three 8-inch (20 cm) round cake pans with parchment paper, then grease the parchment lightly.
In a large bowl, whisk together the almond flour, coconut flour, baking powder and sea salt. Set aside.
In a separate mixing bowl, use a hand mixer to beat the softened butter and sweetener until fluffy and pale (about 2-3 minutes). You’ll notice the aroma of vanilla begin to lift as the butter whips.
Add the eggs one at a time into the butter-sweetener mixture, beating briefly after each addition until fully incorporated. Then beat in the almond milk and vanilla extract until smooth and thick.
Gradually add the dry flour mixture to the wet mixture, folding gently until a thick, smooth batter forms. The batter will be dense but creamy — resist over-mixing.
Divide the batter equally among the three prepared pans, smoothing the tops with a spatula. Bake in the centre of the oven for about 18-22 minutes, or until the tops are lightly golden and a toothpick into the centre comes out clean with a few moist crumbs.
Remove from the oven and allow the layers to cool in the pans for 10 minutes. Then invert onto wire racks and cool completely (about 20 – 30 minutes) before frosting. A warm cake will melt the frosting.
Meanwhile, prepare the frosting: beat the cream cheese and butter together until smooth and creamy (about 1-2 minutes). Then add the powdered sweetener, vanilla extract (and pinch of salt if using). Beat for another minute until light and fluffy. Taste and adjust sweetness if needed.
Once the cakes are fully cooled, place the first layer on your serving plate and spread about ⅓ of the frosting over the top. Repeat with the second layer. Place the third layer on top and frost the top and sides of the cake with the remaining frosting, smoothing it with a spatula.
Decorate with fresh berries and optionally sprinkles or chopped toasted nuts. Chill the cake for 15 minutes to set the frosting slightly before serving. Slice into 12 portions and serve — each slice should present a tall, proud layer of creamy frosting and tender cake beneath.
