Clean and destem mushrooms, then roughly chop into bite size chunks.
Toss mushrooms with enough olive oil to coat, sprinkle liberally with rosemary and thyme, a little salt and pepper, then roast at 350 degrees for 20-30 minutes.
Heat a grill or grill pan to medium high heat, then grill the corn for about 5 minutes on each side, until you can smell the corn. Gently open the husks to allow some steam to escape, and then let rest until cool enough the handle. Remove the husk and silk, and cut off any burnt pieces of corn. Cut corn off of the husk with a large knife.
If fresh corn is not available, sautee frozen sweet corn for a few minutes until some pieces get a little browned.
Mix corn and mushrooms in a bowl. Season for salt and pepper.
To make the sauce:
Peel and slice the shallots into 1/4 inch thick rings. Melt the butter in saucepan and cook the shallots for about 3 minutes until soft (the shallots should be completely submerged in the butter). Scoop out the shallots with a fork and add the corn and mushrooms. Add a little more butter to pan if you lose too much when scooping out the shallots. Turn the heat to medium high, add a pinch of salt, and brown the butter, watching carefully that it doesn't burn. When butter starts to turn medium brown, add a large splash of balsamic vinegar. Let mixture cook about 10 more seconds, then remove pan from the stove and swirl for a more seconds before adding it to the salad.
Toss brown butter with other ingredients, then season for salt and add lemon juice or balsamic vinegar to taste. Add chopped fresh parsley, and a few tablespoons of parmesan cheese.