Mix the dry ingredients (flour, baking powder, salt and sugar).
In a second mixing bowl, whisk together the wet ingredients (eggs, soft butter, lemon juice and buttermilk). Add the lemon zest.
Pour the dry ingredients into the wet ingredients and mix until the ingredients are just combined.
Preheat the Airfryer to 170°c. Spread the batter evenly in muffin tins (paper or silicone).
Bake for approx. 15 minutes. Check after 10 minutes to see how done the muffins are, the baking time may vary depending on the appliance.
Leave the muffins to cool. In the meantime, prepare the icing with powdered sugar and the remaining lemon juice. Stir both together until you have a smooth mixture. Spread over the cooled muffins.
12 servings