Pour the batter into the baking pan. Flatten it with a spatula. Bake for 20 minutes or until lightly brown and a toothpick, inserted into the center, comes out clean. Set aside to cool.
While the crust is cooling, prepare the filling.
Keep (or preheat) the oven at 360° F (180° C).
Using a stand electric mixer, beat the cream cheese until somehow fluffy. Next, add in all the remaining ingredients, except eggs. Mix, starting on medium speed and increasing the speed to high, until well incorporated.
Turn to medium speed and add in eggs, one by one. Mix on high until well combined.
Pour the filling onto the crust. Place in the oven and bake for 15 minutes.
Before you add the topping on, the filling should still be wobbly, but not too runny.
The berry topping
You can prepare the topping while the cheesepie is being baked.
Using a fork, carefully mix the berries with erythritol, lemon juice, and the optional xanthan gum. You can use any type of berries (or none at all).
Using a spoon, scatter the berries on top of the half-baked pie. When done, using your fingers, pinch small pieces of the crumble on top of the berries.
Bake for another 20 to 25 minutes or so. The crumble should turn dark brown, and the berries should not be boiling (anymore). The pie itself might still be a bit wobbly, but it will set when cooled.
Let the Cheesepie cool down at room temperature, then place it in a fridge. You can serve it warm, but it will be much more compact and actually better when cold. It’s best to leave it in the fridge overnight.