Preheat your oven to 350 degrees F. Grease a madeleine pan thoroughly with butter or cooking spray, making sure to coat every ridge.
In a large bowl, whisk together the almond flour, powdered erythritol, baking powder, and a pinch of sea salt.
In a separate bowl, beat the eggs until frothy, about 1 minute. Add the melted butter, vanilla extract, and lemon zest, and whisk until combined.
Pour the wet ingredients into the dry ingredients and stir until a smooth, thick batter forms with no dry pockets remaining.
Spoon the batter into the prepared madeleine molds, filling each one about three-quarters full. Avoid overfilling so they keep their classic shell shape.
Bake for 10 to 12 minutes until the edges are golden and the tops spring back when lightly pressed. Let them cool in the pan for 2 minutes, then gently pop them out onto a wire rack.
Dust the madeleines lightly with powdered sweetener while still slightly warm. These are best enjoyed the same day but will keep in an airtight container for up to 3 days.
