In food processor, combine eggs, soup, onion, garlic powder, & salt; pulse for 30 seconds. Add spinach, bread crumbs, thyme, nutmeg & Parmesan. Blend for another 30 seconds. Set prepared souffle mixture aside.
Preheat oven to 400 F. Remove stems from mushrooms. Wipe mushrooms with a towel as opposed to rinsing them with water. Dip outside of ‘cap’ in bottled, Zesty Italian dressing. Place in a shallow baking dish; stuff caps with souffle mixture & sprinkle with a few more seasoned crumbs. Bake 15 minutes or until souffle mixture is set.
This recipe is easily halved or make the amount of mushrooms you need then bake the rest of the souffle mixture in a casserole dish.
Mushrooms can be made earlier in the day & placed in refrigerator until ready to bake & serve.
If you prefer, use an extra topping such as grated cheddar or bacon bits.