If you haven’t already, cook the chicken breasts by boiling, baking, or pan-searing them, then shred the chicken into bite-sized pieces.
Steam or blanch the broccoli florets by boiling them for about 2-3 minutes in salted water, then immediately transferring them to ice water to stop the cooking process. Drain and set aside.
If you’re using baked potatoes, bake them first (either in the oven or microwave) until tender, then peel and dice them into small chunks.
2. Make the Casserole Filling:
In a large mixing bowl, combine the cream of chicken soup, sour cream, mayonnaise, garlic powder, onion powder, and a pinch of salt and pepper. Stir until smooth.
Add in the shredded chicken, diced potatoes, and steamed broccoli. Stir gently to combine everything evenly.
Stir in 1 1/2 cups shredded cheddar cheese and 1/4 cup Parmesan cheese (if using). The cheese will melt into the filling and make it creamy and delicious.
3. Assemble the Casserole:
Lightly grease a 9×13-inch casserole dish with olive oil or butter.
Transfer the chicken, potato, and broccoli mixture into the prepared casserole dish and spread it out evenly.
Sprinkle the top with the remaining 1/2 cup of shredded cheddar cheese.
4. Bake the Casserole:
Cover the casserole with aluminum foil and bake in the preheated oven for about 25-30 minutes, or until the casserole is heated through and the cheese is melted.
For a slightly golden top, remove the foil during the last 5 minutes of baking to allow the cheese to brown a bit.
5. Serve:
Let the casserole sit for about 5 minutes before serving to allow it to set.
Serve hot and enjoy! This dish is perfect with a side salad or crusty bread.
