1. Preheat your oven to 175°C and line a muffin tin with cupcake liners.
2. In a large mixing bowl, combine the almond flour, coconut flour, erythritol, baking powder, baking soda, and salt. Mix well.
3. In a separate bowl, whisk together the melted butter, eggs, almond milk, lemon zest, lemon juice, and vanilla extract.
4. Gradually add the wet ingredients to the dry ingredients and mix until well combined. Gently fold in the fresh blueberries.
5. Spoon the batter into the prepared cupcake liners, filling them about 3/4 full.
6. Bake for 20-25 minutes or until a toothpick inserted into the center of a cupcake comes out clean.
7. While the cupcakes are baking, prepare the lemon cream cheese frosting. In a mixing bowl, beat the softened cream cheese and butter until smooth and creamy. Add the powdered erythritol, lemon juice, and lemon zest. Beat until well combined.
8. Once the cupcakes are completely cooled, frost them with the lemon cream cheese frosting.
9. Optional: Garnish with additional lemon zest or fresh blueberries.
10. Enjoy your delicious Lemon and Blueberry Keto Cupcakes!