Heat your oven to 350°F and fill a 12-well muffin tin with liners.
Mix the almond flour, coconut flour, baking powder, xanthan gum, and salt in a medium bowl.
In a large bowl, melt the butter, coconut oil, and soften your cream cheese in the microwave for about 30-40 seconds.
Once melted/softened, beat the butter, coconut oil, and cream cheese with an electric mixer.
Add in the sour cream and erythritol and beat again.
Next beat in the eggs and egg white for 1-2 minutes.
Then add in the vanilla extract, lemon juice and lemon zest.
Slowly pour your dry mixture into your wet mixture and incorporate, but don’t over-mix.
Gently fold in the blueberries to the batter.
Divide the batter among each muffin tin liner evenly.
Bake for 25-30 minutes or until tops turn golden brown.
Remove from the oven and let cool.