you can either go the expensive way, get any 35% crit multi implicit foil with the temple mod added cold/cold penetration and try to make a one-stat rare to multimod. Or you go the easy way, get a shaped 35% crit multi implicit foil, craft it as one-stat rare with "Damage penetrates 10% elemental resistances" and multimod that.

The difference is not that huge, though the temple mod is a prefix so you can craft an additional crit multi suffix while on the shaped base you loose that crit multi but instead can craft "gain % of cold damage as extra chaos damage" instead.

While for the first variant the one-stat base already costs a fortune this league the second one costs you probably 1c for the base and some alterations/regals plus annulments. I've chosen the second variant this time.