Peanut Butter Filling:In a large bowl, beat cream cheese, peanut butter and sweetener together until smooth.
Beat in egg, whipping cream, vanilla extract and stevia extract until well combined and smooth. Set aside while you prepare the cake batter.
Cake:Preheat oven to 325F and grease a large bundt pan very well (I like to use both butter and coconut oil spray).
In a medium bowl, whisk together almond flour, cocoa powder, coconut flour, whey protein powder, instant coffee, baking powder, and salt.
In a large bowl, beat butter with sweetener until well combined. Beat in eggs, vanilla extract, and stevia extract.
Beat in half of the almond flour mixture, and then almond milk. Beat in remaining almond flour mixture until well combined.
Transfer about 2/3 of the batter to prepared bundt pan, spreading evenly. Then use a spoon to create a well or a tunnel in the middle of the batter, about 1 inch deep and a few inches wide, all the way around the bundt pan.
Spoon the peanut butter filling into the well. Top with remaining cake batter, covering the peanut butter filling entirely.
Bake 45 to 55 minutes, or until cake is firm to the touch. It should not seem underdone or jiggly at all. Remove and let cool in pan 10 to 15 minutes, then flip out onto a wire rack to cool completely.
Refrigerate at least an hour or two (to help cheesecake filling set).
Chocolate Peanut Butter Ganache:In a small saucepan over medium heat, combine cream and powdered sweetener. Heat until just barely simmering.
Remove from heat and add peanut butter and chocolate. Let sit about 5 minutes to melt chocolate and then whisk until smooth.
Pour over cooled cake (working quickly because it starts to glop up faster than normal ganache).