Ham and Cheese Croissant Bake Recipe

Name: Ham and Cheese Croissant Bake Recipe
Ingredients: 10 large croissants; 6 oz sliced ham; 2 cups shredded gruyere cheese; 4 tablespoons unsalted butter; 1 yellow onion, diced; 1 tablespoon minced fresh thyme leaves; 2 tablespoons minced fresh sage leaves; 2 1/2 cups half and half; 6 eggs; 1 tablespoon dijon mustard; 1 tablespoon whole grain mustard; 1 1/2 teaspoons kosher salt; 1/2 teaspoon ground black pepper; 1/8 teaspoon freshly grated nutmeg; minced chives, for serving; hollandaise sauce, for serving (optional)