Preheat oven to 350°F (180°C). Line two 9-inch round cake pans with parchment paper and oil the sides and bottom with coconut oil. Set aside.
In a large mixing bowl, beat eggs, almond milk, heavy cream, melted coconut oil, and vanilla extract. Set aside.
In another large mixing bowl, whisk together the dry ingredients: almond flour, coconut flour, espresso powder, unsweetened cocoa powder, erythritol, baking powder, and salt. Whisk until all the ingredients are evenly combined and no lumps show.
Make a well in the center of the dry ingredients and pour the liquid ingredients. Stir with a spatula to combine until the batter is smooth.
Evenly divide the batter into the two round pans - it's roughly 2 cups of batter per pan.
Bake both pans at the same time in the preheated oven. Place one cake pan on the center rack and one in the rack just under.
Bake for 35-40 minutes, swapping pan places halfway through baking to make sure both cake layers bake evenly at the same speed. Insert a toothpick in the center of each cake layer to check the cake is cooked through. When the pick comes out clean or with no crumb on it, remove the cake layer from the oven. It's ok if one cooks slightly before the other, remove the cake layer as soon as baked through.
Cool down both cake layers onto a cooling rack for a few hours or overnight before frosting.
Coconut pecan filling
While the cake layers are cooling down, prepare the coconut pecan filling so it's ready when the cake layers are at room temperature.
In a saucepan, whisk together heavy cream, egg yolks, and brown erythritol. Add butter to the saucepan and bring the saucepan over medium heat. Stir occasionally to melt the butter and bring the mixture to a low boil.
Once the mixture is on a light boil, sprinkle xanthan gum, stir in, reduce to low heat and keep cooking for 3-5 minutes until the mixture thickens. Don't over boil, or the caramel will split! Remove from heat and stir in vanilla, toasted chopped pecans, and unsweetened shredded coconut.
Let the mixture cool completely in a large mixing bowl before using. It will thicken even more at room temperature and take 1 hour to be cool.