In a large bowl, beat the eggs until light and foamy. Slowly beat in the sugar, followed by the olive oil and milk. Whisk in the lemon zest and vanilla extract.
Fold in the flour, baking powder, and salt until no clumps remain. Cover the bowl and refrigerate for 30 minutes.
Preheat oven to 425˚F (220˚C). Line muffin tins with paper liners or lightly grease.
Fill each muffin tin with 3/4 of the batter and if desired, sprinkle the tops with sugar. Place in the oven and reduce temperature to 400˚F (200˚C).
Bake the Magdalenas until risen and golden around the edges, 13-15 minutes. Do not open the oven door while baking until they are nearly done. Allow to cool in pan for 5 minutes before removing to wire rack.
Serve warm or at room temperature.