Preheat your oven to 350 degrees F (175 degrees C). Boil salted water in a large pot and cook the peeled and cubed potatoes for about 15 minutes until fork-tender.

Drain the potatoes and return them to the pot. Mash them lightly until smooth yet slightly chunky.

In a skillet, melt butter over medium heat. Sauté diced onion and celery for about 5 minutes, then add minced garlic and cook for an additional minute.

In a mixing bowl, combine the mashed potatoes, sautéed vegetables, crusty bread cubes, parsley, thyme, salt, and pepper; fold until evenly combined.

Whisk together chicken broth and beaten egg in a separate bowl, then pour over the potato-bread mixture and toss gently.

Transfer the stuffing to a greased baking dish and bake for approximately 30 minutes until the top is golden brown.