Preheat your oven to 175 degrees Celsius (350 degrees Fahrenheit).
In a mixing bowl, beat the eggs until frothy.
Next, add in the sour cream and softened butter. Blend until smooth.
Add the lemon juice, the grated zest of the lemon, and powdered erythritol. Blend again until well mixed.
Gradually incorporate the almond flour and baking powder. Mix until smooth.
Prepare a 9x6 inch pan by lining it with parchment paper.
Pour the batter into the prepared pan and spread it evenly.
Place the pan in the preheated oven and bake for 35 to 40 minutes.
Remove the bars from the oven and let cool completely in the pan before slicing.
Carefully lift out of the pan using the parchment paper and cut into squares.
