Prepare orange zest and orange juice.
Beat the eggs and erythritol together until well mixed.
Add almond flour, baking powder, and salt, and mix together.
Melt the butter, add to the mixture, and complete the batter.
Add the orange zest and orange juice to the batter and mix well.
Pour the batter into the madeleine mold.
Bake in a preheated oven at 170°C for 12–15 minutes.