Gather all ingredients before starting the recipe.
Cut 2 hard rolls or 3 slices white bread into 1" cubes and set aside.
Chop 1 medium onion peeled, 2 stalks celery, 1/2 bunch parsley, and slice 1/2 lb mushrooms and set aside.
Heat 1 tbsp oil in a frying pan over medium high heat and add onion and celery and sauté until the onion becomes translucent, about 5-8 minutes, then add the mushrooms, 1/2 bunch parsley chopped, 1 1/2 tsp kosher salt, 1 tbsp sage leaves and 1 tsp ground black pepper . Combine, allowing the mushrooms to let out liquid and begin to soften.
Add bread cubes and combine well and cook for 10-15 minutes.
Check for seasoning, the stuffing should be highly seasoned.
Remove from it from the heat and allow to come to room temperature.
Beat 1 large egg with a fork until slightly frothy and mix well with cooled stuffing. Allow to sit for 5-10 minutes or until the bread has absorbed the egg.
Pre heat oven to 350°F
Spray a loaf pan with vegetable spray and transfer stuffing to pan.
Bake stuffing in a pre-heated oven for 25 - 30 minutes or until the top is golden and the stuffing has set.
