Preheat the oven to 325ºF and grease 2 8-inch round cake pans. Line the bottom of the pans with parchment and grease the parchment as well.
In a medium bowl, whisk together the almond flour, whey protein, coconut flour, baking powder, and salt.
In a large bowl, beat the butter and sweeteners together until light and fluffy. Beat in the eggs one at a time and scrape down the beaters and bowl as necessary. Beat in the vanilla extract
Add the dry ingredients to the bowl and beat until well combined. Add just enough liquid to thin the batter to a scoopable and easily spreadable consistency.
Divide the batter between the two cake pans and spread to the edges. Smooth the tops and bake 20 to 25 minutes, or until the edges are golden and the tops are firm to the touch.
Remove and let cool in the pans, then flip out onto a wire rack. Be sure to peel off the parchment paper if it sticks to the cake layers.
Caramel Glaze
Prepare a double batch of the Sugar Free Caramel Sauce but DO NOT add the additional water at the end of the recipe. Be sure to use a large saucepan (at least 3 quarts) as it will bubble up quite a bit.
Let the sauce cool down to room temperature. It should be quite thick at this point, but still pourable, and it will continue to thicken as it cools.
**If your caramel sauce is too thin, you can bring it back to a simmer and continue to cook it a few more minutes to help it thicken. At this point, you can also whisk in a bit more thickener like xanthan gum or glucomannan.
Place one layer of cake on a serving plate and pour about ⅓ of the caramel sauce on top. Carefully spread to the edges with an offset spatula and let sit another 10 to 15 minutes to thicken further.
Place the second layer of cake on top. Pour some of the caramel over the top, letting it drip down the sides, spreading it over the top and sides as you go. Continue until the top and sides are well covered. Alternatively, you can simply let it drip down the sides and not spread it over.
Refrigerate the cake at least 1 hour to help set the glaze.
Notes
Storage Information: Store the cake in a covered container in the fridge for up to 7 days. It can also be frozen for several months.