Melt the butter in a small pan (18-20cm diameter) over low heat (e.g., level 3 of 9).
Add the 4 whisked eggs and stir continuously, without stopping. No scrambled egg should settle at the bottom.
If the egg scrambles too much, immediately remove the pan from the hob and reduce the heat. Put it back on the hob when it feels right.
Stir until the egg emulsifies with the melted butter and reaches a creamy consistency (can take up to 10 minutes).
Once the egg has your desired creaminess, spread the mixture evenly on the bottom of the small pan and let it sit briefly until a stable skin forms on the underside of the egg.
Tilt the pan and use a spatula to roll the egg from top to bottom.