1. If you are using frozen scallops, make sure they are completely thawed.
If they are fresh, clean them and remove the coral if desired. The most important step: thoroughly dry each scallop on all sides with paper towels.
They should not be wet on the surface, otherwise they will not brown.
Lightly season with salt and pepper on both sides.
2. Choose a large skillet (the scallops should not overlap).
Heat it over high heat. Add the olive oil, then the butter.
Wait for the butter to melt, stop "singing" (sizzling), and turn a light hazelnut color with a biscuit smell.
This is a sign that the skillet is at the right temperature.
3. Gently place the scallops in the hot skillet, making sure they are well spaced apart.
Do not touch them for 1 minute straight!
This uninterrupted contact with the hot skillet will create a beautiful golden crust.
4. Using tongs or a spatula, flip the scallops.
Let the other side cook for an additional 1 minute (or 1 minute 30 seconds if they are very thick).
Do not baste the scallops with the butter during cooking, as this could cause them to boil.
5. Immediately remove the scallops from the skillet to stop the cooking process (otherwise they will become rubbery).
Serve immediately, sprinkled with a little fleur de sel if desired, with your choice of accompaniment (leek fondue, rice...).