1) Preheat oven to 375F. 2) Arrange croissant pieces on baking sheet and bake until lightly toasted, about 10-15 minutes. 3) Butter a 13 x 9 inch baking dish or oval casserole. 4) Meanwhile, in large pot over medium-high heat, cook bacon, stirring occasionally, until crisp; move to paper towel-lined plate. 5) Remove all but 2 tbsp of fat. Add onion and celery and cook, stirring, until onions are softened, about 5-6 minutes. 6) Add celery leaf, sage and garlic. Add white wine and cook, stirring, until wine has almost completely evaporated, about 15 minutes. Remove from heat. 7) Whisk together broth, eggs, salt and pepper. 8) Stir into vegetable mixture. Add croissant pieces and bacon; mix just until combined. Scrape into prepared baking dish. 9) Return to oven and bake, uncovered, until browned and crispy on top, about 15-20 minutes.