Preheat the oven to 350°F. Line the bottom of an 8-inch round cake pan with parchment paper and lightly grease the sides with oil or butter.

In a medium bowl, whisk together the almond flour, coconut flour, baking powder, baking soda, and sea salt until well combined and free of lumps.

In a large bowl, whisk the eggs and granulated monk fruit sweetener until smooth and slightly foamy.

Whisk in the melted and cooled coconut oil, vinegar, almond milk, vanilla bean paste, 1 teaspoon lemon extract, lemon juice, and grated lemon peel until fully combined.

Add the dry ingredients to the wet ingredients and gently fold with a spatula until just combined and no dry spots remain. Do not overmix.

Pour the batter into the prepared pan and smooth the top with a spatula.

Bake for 18 to 20 minutes, or until the edges are golden and a toothpick inserted in the center comes out clean.

Let the cake cool in the pan for 10 minutes, then run a knife around the edge, remove from the pan, and transfer to a wire rack to cool completely.

Once the cake is fully cool, prepare the frosting. In a large bowl, beat the softened butter and cream cheese with a hand mixer until very smooth and creamy.

Gradually add the powdered monk fruit sweetener, mixing on low at first, then increasing speed until the frosting is smooth and thick.

Beat in 1/2 teaspoon lemon extract and 1 teaspoon lemon zest, then add the almond milk and mix until the frosting is smooth and spreadable.

Place the cooled cake on a serving plate. Spread the lemon cream cheese frosting evenly over the top and sides of the cake.

Chill the frosted cake in the refrigerator for at least 2 to 3 hours to allow the frosting to set and the crumb to firm for clean slices.

Garnish the top with thin lemon slices just before serving. Slice with a sharp knife, wiping the blade between cuts for neat slices.