I don’t own a standard blender, just an immersion blender. Will that whip cream? I will probably need to grind the nuts in a food processor

Use Whole Foods brand heavy cream. It's all cream with zero no added thickeners. It'll whip, by hand, in less than five minutes. It's a beautiful product. In fact it's so thick, it lumps a little at the bottom of the carton. You need to pound the bottom of the carton against the heel of your hand, and shake, to get it mixed back in. It's the real thing.

Hi! In that case, you can try to do both in a food processor: blitz the nuts, then add and whip the cream.