Preheat your oven to 350°F and spread bread cubes on a large baking sheet. Toast for 10-12 minutes until lightly golden and dried out, then transfer to a large mixing bowl.
In a large skillet over medium heat, melt the butter and sauté the onion and celery for 5-6 minutes until softened and fragrant.
Add the sliced mushrooms to the skillet and cook for another 8-10 minutes until they release their moisture and turn golden brown.
Stir in the minced garlic, chopped sage, and thyme, cooking for another minute until super aromatic.
Pour the mushroom mixture over the toasted bread cubes and toss everything together.
In a separate bowl, whisk together the broth and beaten eggs, then pour over the bread mixture along with the parsley, salt, and pepper.
Gently fold everything together until the bread is evenly moistened (don't overmix or it'll get mushy!).
Transfer to a greased 9x13-inch baking dish and cover with foil.
Bake covered for 25 minutes, then remove the foil and bake for an additional 15-20 minutes until the top is crispy and golden.
Let it rest for 5 minutes before serving – the hardest part is waiting!