Preheat the oven to 180C/350F. Grease a 9-inch cake pan and line with parchment paper. Set aside.
In a small bowl, whisk together the almond flour and baking powder and set aside. In a mixing bowl, whisk together the rest of the ingredients until completely combined.
Gently add in the dry ingredients and mix well. Transfer the batter into the lined cake pan and bake for 35-40 minutes, or until a skewer comes out clean. Let the cake cool completely before frosting.
To make the frosting
In a mixing bowl, add all the ingredients and beat together until combined. If too thin, add more sugar free powdered sugar.
Notes
Cake layers: This makes a single-layer cake. For a layer cake, double the ingredients. For a 3-tier cake, triple the ingredients. Sweetener: My original recipe called for erythritol or monk fruit, but after retesting it, allulose was more consistent and baked much better. Leftovers: Keep in the fridge, covered, for up to 7 days, or in the freezer for up to 6 months.