Baked Potato Chicken Broccoli Casserole

The first time I made this casserole, I was trying to use up leftover roasted chicken from Sunday dinner. My kitchen smelled like comfort food heaven, and my husband kept wandering in to ask if it was ready yet. That night we ate it straight from the baking dish while watching a movie, and I knew this recipe was staying in our regular rotation forever.

Last winter my sister came over feeling completely drained from work, and I threw this together while she sat at my counter drinking wine. She took one bite and literally stopped talking mid-sentence, then asked for the recipe before she even finished her plate. Now she makes it for her family every Sunday evening.

Ingredients

• 2 cups cooked chicken breast: Rotisserie chicken works beautifully here, or use leftover roasted chicken for the best flavor
• 4 medium russet potatoes: Dice them evenly so they cook through without turning mushy
• 2 cups broccoli florets: Fresh broccoli gives you those perfect tender-crisp bites throughout
• 1 small onion: Finely chopped so it melts into the creamy sauce rather than staying chunky
• 2 cloves garlic: Minced fresh garlic adds that aromatic depth you cannot get from powder
• 1 cup sour cream: Full fat sour cream creates the richest, most velvety sauce base
• 1 cup shredded cheddar cheese: Reserve half for topping to get that gorgeous golden cheesy crust
• ½ cup milk: Whole milk works best, but whatever you have in the fridge will do
• 2 tablespoons unsalted butter: Melted into the sauce for that extra savory finish
• 1 teaspoon salt: Adjust this based on whether your cooked chicken was already seasoned
• ½ teaspoon black pepper: Freshly cracked pepper makes a noticeable difference
• ½ teaspoon paprika: Adds a subtle warmth and beautiful color to the sauce
• ½ teaspoon dried thyme: Earthy and aromatic, thyme pairs perfectly with both chicken and potatoes

Instructions

Preheat your oven to 400°F:

Grease a 9x13 baking dish with butter or cooking spray while the oven heats up

Boil the diced potatoes:

Cook them in salted water for 8 to 10 minutes until they just give way when pierced with a fork

Steam the broccoli:

Give the florets 3 to 4 minutes until they turn bright green but still have some crunch

Combine the fillings:

Mix the cooked potatoes, broccoli, chicken, onion, and garlic in a large bowl

Whisk the creamy sauce:

Blend together sour cream, milk, melted butter, 1 cup cheese, and all the seasonings until smooth

Coat everything evenly:

Pour the sauce over the potato mixture and stir gently until every piece is covered

Transfer to baking dish:

Spread the mixture evenly and sprinkle the remaining cheese across the top

Bake until golden:

Let it cook uncovered for 25 to 30 minutes until the sauce bubbles and the cheese turns golden brown

Rest before serving:

Give the casserole 5 minutes to set so portions hold together when you scoop them

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My toddler who normally refuses anything green actually ate the broccoli in this without complaint, and I may have done a little victory dance right there in the kitchen. Something about that creamy sauce makes all the vegetables feel like comfort food instead of something healthy.

Make It Your Own

Sometimes I swap Greek yogurt for the sour cream when I am trying to be a little healthier, and honestly nobody notices the difference. The texture stays just as creamy and rich.

Perfect Pairings

A crisp green salad with vinaigrette cuts through the richness perfectly. We also love roasted asparagus or steamed green beans on the side when we want something lighter.

Make Ahead Magic

You can assemble this entire casserole the night before and keep it covered in the refrigerator. Just add about 10 minutes to the baking time since it will be cold going into the oven.

• Let the dish come to room temperature for 20 minutes while the oven preheats
• Cover with foil for the first 20 minutes, then remove it to finish browning the top
• The cheese on top might burn if baked from cold, so watch it closely

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This is the kind of recipe that makes people feel loved without you saying a word.

Recipe Questions & Answers

→ Can I use leftover rotisserie chicken?

Yes, leftover rotisserie chicken works perfectly in this casserole. Simply shred or cube the meat and add it during step 4 when combining all the ingredients together.

→ Can I make this casserole ahead of time?

Absolutely. Assemble the entire casserole, cover tightly, and refrigerate for up to 24 hours before baking. You may need to add 5-10 minutes to the baking time if baking cold from the refrigerator.

→ What can I substitute for sour cream?

Greek yogurt makes an excellent lighter substitute for sour cream. You can also use plain Greek yogurt or a combination of cream cheese and milk for similar creaminess and tang.

→ Do I need to precook the potatoes and broccoli?

Yes, precooking ensures the vegetables reach the right tenderness. Potatoes need 8-10 minutes boiling, while broccoli only requires 3-4 minutes of steaming to maintain texture without becoming mushy during baking.

→ Can I freeze this casserole?

You can freeze the assembled, unbaked casserole for up to 3 months. Thaw overnight in the refrigerator before baking. Alternatively, freeze leftovers in individual portions for quick reheating.

→ What other cheeses work well?

While sharp cheddar provides classic flavor, you can substitute Monterey Jack, Colby Jack, or Gruyère. Mixing cheeses creates depth—try half cheddar and half Jack for a milder, creamier result.