Croissant Stuffing with Sausage and Apples

Preheat oven to 350 degrees F. Heat olive oil in a large skillet over medium-high heat. Add sausage and cook, breaking up with a wooden spoon, until browned, 5 minutes. Transfer to a large bowl using a slotted spoon. Add 2 tablespoons butter to skillet along with celery, leeks, and apple. Season with 1 teaspoon salt and 1/4 teaspoon black pepper and cook, stirring often, until tender, 6 to 8 minutes. Add wine and cook, stirring, until almost all evaporated, 2 minutes. Transfer vegetable mixture to bowl with sausage and add croissant pieces, sage, and thyme and toss to combine. In a separate medium bowl, whisk together eggs and 2 cups broth. Pour over croissant mixture and toss until evenly moistened, adding more broth 1/4 cup at a time until croissant pieces seem hydrated (you might not use it all). Butter a 3-quart baking dish and add stuffing. Dot with remaining 4 tablespoons butter and cover dish with foil. Bake until a knife inserted in the center of the stuffing comes out warm, 30 to 35 minutes. Increase heat to 425 degrees F and continue to bake until top is deeply golden, 10 to 15 minutes more. Let rest 10 minutes before serving.