Preheat oven to 325F. Grease a bundt cake pan VERY well and then dust with a few tbsp of almond flour. Pro Tip: double-grease your pan to help prevent sticking. Use a solid fat first, like butter or coconut oil, and then a spray like coconut or avocado.
In a medium bowl, whisk together the almond flour, coconut flour, whey protein, baking powder, and salt.
In a large bowl, beat the butter and the sweetener together until light and creamy. Beat in the eggs and vanilla extract. Beat in the almond flour mixture and then beat in the whipping cream and water until well combined.
Transfer the batter to the prepared baking pan and smooth the top. Bake 50 to 60 minutes, until golden brown and the cake is firm to the touch. A tester inserted in the center should come out clean.
Butter Glaze:In a small saucepan over low heat, melt the butter and sweetener together. Whisk until well combined. Whisk in the water and vanilla extract.
While the cake is still warm and in the pan, poke holes all over with a skewer. Pour the glaze over and let cool completely in the pan.
Gently loosen the sides with a knife or thin rubber spatula, then flip out onto a serving platter. Dust with powdered sweetener.
Serve with lightly sweetened whipped cream and fresh berries.
Serves 16 (this is a big, rich cake!). Each serving has 3.04g NET CARBS.