1. Preheat oven to 375°F (190°C) and grease a casserole dish well.
2. In a skillet over medium heat, cook ground turkey, breaking it apart as it goes, until properly browned — about 6-7 minutes. Wait for real color, not just gray cooked-through meat.
3. Add chopped celery, diced onion, minced garlic, dried thyme, salt, and black pepper to the skillet. Cook until vegetables are genuinely tender, about 6-8 minutes, stirring regularly.
4. Stir in chicken broth and simmer for 5 minutes until the liquid reduces slightly and everything comes together cohesively.
5. Transfer the turkey mixture to the prepared casserole dish and spread evenly.
6. Scatter shredded cheddar generously over the top.
7. Mix breadcrumbs with melted butter until every crumb is coated and sprinkle evenly over the cheese layer.
8. Bake for 25-30 minutes until bubbly, golden brown, and smelling incredible.
9. Let rest for a few minutes before serving — it portions much more cleanly after a short rest.

Nutrition Information (Per Serving):

• Calories: 355
• Carbohydrates: 12g
• Protein: 34g
• Fat: 18g
• Fiber: 2g
• Sodium: 720mg
• Key vitamins/minerals: Vitamin K (30% DV from celery), Calcium (22% DV from cheddar), Vitamin B6 (40% DV), Zinc (25% DV)
• Note: Ground turkey provides lean complete protein while celery contributes meaningful vitamin K — a genuinely nourishing combination in a satisfying one-dish bake.

Notes:

• Cook celery until completely tender on the stovetop — undercooked celery releases water in the oven and makes the casserole watery
• Brown the turkey properly before adding vegetables — this builds the flavor foundation for the entire dish
• Let the casserole rest at least 5 minutes before serving so it holds together when scooped

Storage Tips:

• Refrigerate covered for up to 3 days
• Reheat in a 350°F oven covered with foil for 15 minutes for best texture and topping crunch
• Freeze assembled but unbaked (without breadcrumb topping) for up to 3 months — add topping right before baking

Serving Suggestions:

• Serve with a simple green salad dressed with lemon vinaigrette to cut through the richness
• Pair with roasted broccoli or green beans for a complete and balanced meal
• Crusty bread alongside for scooping up any cheesy bits from the dish
• A dollop of plain Greek yogurt on the side works as a lighter alternative to sour cream

Mix It Up (Recipe Variations):

• Cream Cheese Version: Stir 2-3 tablespoons of softened cream cheese into the turkey mixture before transferring to the casserole dish for a richer, creamier result that feels more indulgent
• Holiday Gruyère Twist: Swap half the cheddar for gruyère and add a pinch of nutmeg to the turkey mixture for a more sophisticated, French-inspired flavor profile
• Kid-Friendly Corn Addition: Stir a cup of frozen corn into the turkey mixture before baking for sweetness, color, and a flavor combination that wins over younger eaters every time

What Makes This Recipe Special: Cooking the celery and onion until completely tender on the stovetop before the casserole ever goes in the oven is the technique that separates this from basic ground turkey bakes — it eliminates excess moisture, fully develops the vegetable flavor, and ensures the finished casserole has a cohesive, satisfying texture rather than a watery, unevenly cooked result. The combination of melted sharp cheddar and buttered breadcrumbs creates a topping that delivers both richness and crunch in every bite, which is what makes this turkey and celery casserole genuinely worth coming back to.