Wash and dry spinach well. Remove tough stems. Rough chop remaining leaves and soft stems.
In a saute pan, drizzle 2 tsp EVOO. Turn heat to med-high. Add corn. Saute until corn starts to brown. Add in cashews, saute for another minute - do not burn cashews.
Pour cashews/corn in a small bowl, set aside.
In same saute pan, add 1 Tbsp apple cider vinegar, and an optional drizzle of EVOO. Add spinach.
Turn heat to medium and cover spinach with a loose lid or piece of tin foil to 'steam' and wilt the leaves. Do not over wilt. when the leaves are tender, add the corn and cashew mixture. Fold lightly. Transfer this mixture to serving bowl. Grind black pepper over top.
In same saute pan, add 1 Tbsp EVOO and mushrooms. Saute until tender. Add in chopped parsley and continue to saute. Towards end of saute, add in the balsamic vinegar or truffle cream of balsamic. Toss well. Add sea salt. Transfer shiitakes to your serving bowl - gently layer on top of spinach.