First, pre-heat your oven to 350 degrees and prepare an 8" square baking pan with parchment paper. Then in a large bowl, take two of the four eggs and separate the whites from the yolks. Set the yolks in a large bowl and set the egg whites in another bowl to the side.
4 large eggs
In the large bowl, add the two remaining eggs to the egg yolks. Beat them with a mixer until combined.
4 large eggs
Next, add the melted butter, vanilla extract, and apple cider vinegar to the beaten eggs. Whisk them to combine.
1/2 cup butter, 2 tsp vanilla extract, 2 tsp apple cider vinegar
Then, in a separate medium-size bowl, mix the granulated white sweetener, baking powder, and almond flour. Then, fold it into the egg mixture and stir to combine.
Now, go back to the egg whites and beat them with a mixer until they form soft peaks. The egg whites will be ready when you turn your bowl upside down without them sliding out. Fold this into the cake batter and set aside.
4 large eggs
Cinnamon Crumble
To make the cinnamon crumble, add the brown monk fruit sweetener, almond flour, nutmeg, cinnamon, and chopped walnuts or pecans.
1/3 cup erythritol, 1/4 tsp nutmeg, 3 tsp cinnamon, 4 tbsp almond flour, 1 cup walnuts, 1/3 cup butter
Then add the melted butter and mix with a fork until well combines. It should create a moist but grainy consistency like pictured above. If necessary, you can add another 1/2 tablespoon of almond flour.
Now in the 8" square pan, pour half of the keto coffee cake batter. Then add a layer of the cinnamon crumble on top of the batter, and extend it evenly. Next, add the remaining keto coffee cake batter and then top with the rest of the cinnamon crumble.
Bake for 25-28 minutes or until an inserted toothpick comes out clean. Due to the almond flour and cinnamon crumble, a moist cake is desirable.
Cream cheese icing
Prepare the cream cheese icing by mixing the cream cheese with the heavy cream and powdered erythritol. Adjust thickness and sweetness to taste by adding the powdered sweetener a little at a time.
1 tbsp cream cheese, 1/3 cup heavy cream, 1 tbsp powdered erythritol
Once your keto coffee cake is finished baking, let it cool completely. Then drizzle with the icing before serving.
Notes
You can substitute almond flour with pecan or sunflower flour.
It is better for the cake to be slightly undercooked than overcooked.
All of the sugar substitutes can be replaced by regular sugar, but stick to granulated, brown, and powdered sugar.