Beat together the eggs and sugar until the sugar has dissolved and the mixture becomes paler and with little bubbles in it.
Separately, mix the flour, baking powder and salt. Add this mixture to the egg-sugar mixture along with the oil, milk and lemon zest. Mix until smooth and well combined. Cover the mixture and refrigerate for approximately 30 minutes.
Towards the end of the chilling time, preheat the oven to 450F/230C. Line a muffin tin with 12 liners.
Take the mixture out of the fridge and spoon the mixture evenly into the muffin liners - don't mix the batter, just scoop it out and just fill the liners to around ¾ full.
If you like (recommended), sprinkle a little sugar over the top of each of the muffins then place them in the oven and immediately reduce the temperature to 400F/200C.
Bake the muffins for approximately 15 minutes, turning once after around 10-12 minutes, if needed, to help the 'humps' be even in the middle (but don't open the oven before at least 10 minutes to make sure they rise properly).
Allow to cool a minute or two before removing from tin onto a cooling rack.
Video
Notes
You can use a light or more fuller-flavored olive oil as you prefer for this - a more flavorful extra virgin olive oil is going to come through flavor-wise, for me in a good way but may not be to all tastes.