Tryin to craft an helmet with -9% cold res on nearby ennemies, any1 know the recipe for that kind of thing ?

3 soc or 4 soc resonnator ?

Resonator with frigid fossil will give you a chance to roll it.

If you go to Poe.db, select an item type, you can then check different fossils and see what mods are more likely to roll as a result

Probably just go with a 2socket (Frigid + Pristine) and try for the -9cold and some decent life rolls.