Set oven to 350°. Butter an 8 × 8 baking dish and set aside.

Pull off stubs (do not discard) and wash cap tops under cold running water. Lay them top side down on paper towels to dry while you prepare the other ingredients.

Place the sun dried tomatoes in a bowl of very hot water - not boiling.

Smash and finely dice a large clove of garlic. Take half a red onion and slice off 2 - 1/4" slices & dice them. Take 4-5 larger mushroom stems and finely dice. Lastly dice the tomatoes. BTW, if you threw out the stems (like I have) take 1, or 2, of the smallest mushrooms and use them as a replacement.

Over a medium heat in a non-stick pan melt 2 tablespoons of butter.

Once the butter is frothy add onions & cook about 1 minute. Add diced garlic, sun dried tomatoes and mushrooms. If it seems dry, add another pat of butter. Add about a teaspoon of extra virgin olive oil. Cook for about a minute then add herbs, salt & pepper.

While the onions are cooking place the stale bread into a gallon plastic bag and break it up into small pieces. Don't worry if there are bread crumbs - it's all going into the filling.

When the onions look translucent put in a splash of balsamic vinegar and very soon it will evaporate. Take off the heat. Throw in the bread, stir well to incorporate and add up to 3/4 of a cup of chicken broth. There should be just enough to moisten the bread not make soup. Let cool.

In a bowl add 2-3 tablespoons of extra virgin olive oil and dip only the tops of the mushrooms making sure to get the sides. Add more oil as you need to.

Place caps in baking dish and start to mound filling into each cap using all the stuffing. Finish with grated cheese. Bake about 30 minutes.