Croissant Stuffing with Sausage and Apples

Name: Croissant Stuffing with Sausage and Apples
Ingredients: 1 tbsp. extra-virgin olive oil; 12 oz. breakfast sausage, casings removed if necessary; 6 tbsp. butter, plus more for baking dish, divided; 4 celery stalks; 4 medium leeks, finely chopped; 1 sweet-tart apple, such as pink lady or granny smith, cored and chopped; 0.5 c. dry white wine; 10 c. torn croissants (about 8 croissants), dried overnight; 2 tbsp. freshly chopped sage; 2 tbsp. freshly chopped thyme; 2 large eggs; 3 c. low-sodium chicken or vegetable broth