Begin by setting your oven rack in the center and preheating your oven to 350ºF (180ºC). Prepare an 8-inch (20 cm) springform pan by lining it with baking paper.
In a large bowl or the bowl of a stand mixer fitted with a whisk attachment, combine the eggs, egg white, caster sugar, light brown sugar, and lemon zest. Beat the mixture on high speed for about 10 minutes or until the mixture becomes pale, thick, and triples in volume. Depending on your mixer, this may take up to 12-14 minutes, especially if using a hand mixer.
Tip: When the mixture reaches the “ribbon stage,” the batter will form a ribbon-like trail on the surface when you lift the whisk.
Add the milk and yoghurt, then briefly whisk until the ingredients are well incorporated.
Sift in the almond flour, gluten-free flour blend, baking powder, xanthan gum, and salt. Mix thoroughly until the dry ingredients are fully integrated, and there are no remaining lumps of flour.
With the mixer running on medium-high speed, gradually pour in the melted butter. Once the butter is fully combined, whisk the batter on high speed for an additional 20-30 seconds to achieve a smooth, silky consistency.
Pour the prepared batter into the lined springform pan and smooth the surface evenly. Sprinkle the flaked almonds over the batter, ensuring the entire surface is covered and only a little cake batter is visible beneath the almond layer.
Bake in the preheated oven for 45-50 minutes or until the cake is well-risen, a deep golden brown on top, and a toothpick inserted into the center comes out clean or with a few moist crumbs. If the almonds begin to brown too quickly, cover the cake loosely with aluminum foil (shiny side up) to prevent over-browning and continue baking.
Tip: For a richer, more indulgent texture, consider slightly underbaking the cake by a few minutes. This method will create a soft, slightly fudgy center reminiscent of frangipane, contrasted by a cake-like outer layer. In this case, you’re looking for a toothpick to come out with a touch of semi-baked batter.
Once baked, let the cake cool in the springform pan for 10-15 minutes. Carefully remove it from the pan and transfer it to a wire rack to cool completely or until it’s warm to the touch.
This almond cake is best enjoyed warm or at room temperature.