Prepare the mushrooms by cleaning them and removing the stems.
Finely chop the stems.
Heat the butter in a large pan over medium heat.
Add the chopped mushroom stems and minced garlic to the pan. Saute for 4 to 5 minutes. Once cooked, remove the mushroom stems from the heat and set aside for 10 minutes to cool.
In a bowl, combine the cooled mushroom stems, cream cheese, ⅓ cup grated Parmesan, onion granules, thyme, oregano, salt, and pepper.
In a separate bowl, combine the remaining ⅓ cup grated Parmesan, breadcrumbs, and pecans.
Place the mushroom caps onto the prepared baking tray.
Using a teaspoon, fill the mushroom cups to the brim with the cream cheese mixture.
Carefully top each mushroom with the breadcrumb mixture.
Bake in the oven for 10 to 12 minutes, until the mushrooms have softened and the tops are crisp.
Serve the stuffed mushrooms right away, optionally garnished with parsley.