Stuffin Muffins

Name: Stuffin' Muffins
Ingredients: 4 tbsp. butter; 1 lb. pork sausage, casings removed; 1 Medium Onion, Diced; 2 cloves garlic, minced; 1 1/2 c. celery, diced; 1 egg, lightly whisked; 1 tsp. thyme; 1 tsp. rosemary; 1 tsp. Ground sage; 8 cups bread cubes (about 1 loaf); kosher salt; Freshly ground black pepper; 2 c. chicken broth; nonstick cooking spray