Cook them...not my specialty haha. No but my mom took care of them. She blanched them and put them in the freezer. Then she usually adds them to all kinds of dishes. She has so much stuff in her freezers, she has 3 of them! And she still doesn't think she has enough space.
Yes I do hope you'll find some new mushrooms for you in Europe. Of course you are always welcome to Sweden, even though I understand that might be somewhat of a detour.