Pre-heat oven to 350*F.
In a bowl, whisk together your dry ingredients including; almond flour, coconut flour, arrowroot starch, baking powder, baking soda, nutmeg and salt.
In a measuring cup or small bowl, add your coconut milk and vinegar and set aside.
In another very large bowl, beat together the butter and sweetener until light and fluffy (~2 min) then add your egg yolks and vanilla extract and beat again until smooth.
Finally, in another bowl, beat your egg whites until the turn pretty much solid white in color (see photo).
Add your dry ingredients as well as the cream/vinegar to the beaten butter and sugar mixture. Mix well until no flour is left visible and a thick dough forms.
Gently stir in the egg whites until no longer visible.
Press the cake into the bottom of a greased 9x13inch pan and bake for 23-27min or until golden brown around the edges and a toothpick comes out clean.
Once the cake is fully cooled, poke holes throughout it using the opposite end of a wooden spoon (see photo for reference). Poke all the way to the bottom of the cake.
You can then make the pudding simply by adding the dry mix to a bowl and beating with the cream and coconut milk until it just starts to thicken (don't over-beat it). You want it still liquid enough to be able to pour into the holes in the cake.
Use a spatula to spread the mixture over the top of the cake a few times to fill the holes and form an even layer.
Refrigerate for 30-40min.
After refrigeration, you can make your chocolate topping by microwaving the heavy cream in a large glass measuring cup or bowl until hot (~1min- 1min 30s). Add your chocolate chips and butter to the hot cream and leave for 40s before mixing well until everything is melted, silky and the mixture is a dark brown colour.
Pour the mixture as evenly over the cake as you can, then use a spatula to even it out. Refrigerate the whole cake again for at least 30-45min before slicing and serving. Enjoy your Keto Boston Cream Poke Cake! **Pro tip, once the cake has chilled and set, I actually like serving it at room temperature or heated for just 15-20s in the microwave to take the chill off. It gets so much softer!**