Make room for high protein harvest casserole at your next family dinner. Explore a hearty fall recipe made for generous scoops and plates worth refilling!

Golden butternut squash, tender chicken, creamy white beans, and a crackly cheddar and pumpkin seed topping make this high protein harvest casserole a dinner worth pulling your favorite baking dish out for!

What Makes This Casserole Special

This recipe gets its personality from cider, sharp white cheddar, and a golden pepita crust. Reducing cider with onions concentrates its apple flavor without leaving a puddle underneath dinner, while Dijon keeps sweet squash from taking over.

My vote is for an extra-sharp cheddar here, because a modest amount brings plenty of character, and those little toasted pumpkin seeds give each bite a welcome crunch!

White beans nestle between chicken and squash, adding creamy little pockets that make every spoonful more interesting.

From a cooking perspective, cannellini beans are especially useful because their mild flavor lets sage, cider, and cheddar shine.

Ingredients

For the Squash and Filling

• 1½ pounds peeled, seeded butternut squash, cut into ½-inch cubes, about 4½ cups or 680 g
• 3 cups cooked, chopped skinless chicken breast, about 1 pound or 450 g, weighed after cooking; rotisserie breast meat works well
• 1 can cannellini beans, 15 to 15½ ounces, rinsed and thoroughly drained, yielding about 1½ cups or 250 g of beans
• 1 medium yellow onion, finely diced, about 1 cup or 150 g
• 3 packed cups baby kale, about 3 ounces or 85 g, with any tough stems removed and larger leaves roughly chopped
• 3 garlic cloves, finely minced
• 1 tablespoon finely chopped fresh sage, or 1 teaspoon dried rubbed sage
• ½ cup unsweetened apple cider, 120 ml, meaning nonalcoholic drinking cider, not cider vinegar
• 2½ tablespoons olive oil, divided between roasting and sautéing
• ¾ teaspoon fine sea salt, divided, plus a little more only if needed
• ¾ teaspoon freshly ground black pepper, divided

For the Creamy Cider Dijon Sauce

• 2 cups 2% cottage cheese, about 16 ounces or 450 g
• ¾ cup low-sodium chicken broth, 180 ml, plus 1 to 2 tablespoons only if needed
• 1½ tablespoons Dijon mustard
• 1 teaspoon apple cider vinegar
• 1 tablespoon cornstarch, about 8 g
• ¾ cup freshly grated sharp white cheddar, 3 ounces or 85 g, divided

For the Pumpkin Seed Topping

• ½ cup panko breadcrumbs, about 30 g
• ¼ cup raw, unsalted pepitas, about 30 g; these are green pumpkin seeds without shells
• ½ tablespoon olive oil
• A little oil or cooking spray for greasing your baking dish

Servings: 6 generous main dish portions

Estimated protein: About 40 to 45 grams per serving, depending on ingredient brands

Prep time: 20 minutes, using cooked chicken and peeled squash
Cooking time: 60 to 70 minutes, with stovetop work done while squash roasts
Resting time: 10 minutes
Total time: Approximately 1 hour 30 minutes to 1 hour 40 minutes
Oven temperatures: 425°F for roasting, then 375°F for baking

How to Make High Protein Harvest Casserole

1. Heat your oven to 425°F (220°C) with a rack near the middle, and lightly grease your baking dish so those cheesy edges release easily later. Check your squash pieces before you do anything else: aim for fairly even ½-inch cubes, because a mixture of tiny scraps and chunky boulders will give you very different cooking results.

If you bought precut squash, spend a minute trimming oversized pieces. I would gladly take that small job now in exchange for evenly tender squash at dinner!

2. Spread squash across a large rimmed baking sheet and toss with 1½ tablespoons olive oil, ½ teaspoon salt, and ¼ teaspoon pepper. Give pieces a little breathing room, then roast for 25 to 30 minutes, turning after about 15 minutes, until a fork slips through easily and several edges have turned golden brown.

Use two pans if yours looks crowded, rotating their positions halfway through. Don’t skip this roasting step, because it develops sweetness and lets moisture escape before squash meets sauce; a crowded pile mostly steams, and we are after browned edges!

3. While squash roasts, warm 1 tablespoon olive oil in a large skillet over medium heat, add onion and remaining ¼ teaspoon salt, and cook for 5 to 7 minutes, stirring occasionally, until softened with a few pale golden edges. Lower heat if onion darkens before it softens.

Stir in garlic and sage for about 30 seconds, just until fragrant, then pour in apple cider and scrape up any golden bits. Simmer for 4 to 6 minutes, until liquid has reduced by roughly half, then add kale and stir for another 2 to 3 minutes, until wilted.

You want moist onions and tender greens without a large puddle; if liquid collects, cook another minute or two, then remove from heat.

4. Blend cottage cheese, ¾ cup broth, Dijon, cider vinegar, and remaining ½ teaspoon pepper for 30 to 60 seconds, stopping to scrape down the sides if needed, until smooth and creamy.

Taste before adding cornstarch, keeping in mind that chicken and cheddar will contribute salt, then add only a small pinch if your sauce needs it. Add cornstarch and blend for another 10 seconds.

Sauce should pour in a thick ribbon; if your cottage cheese is unusually dense, add 1 to 2 tablespoons extra broth. Blending thoroughly is worth those few extra seconds, because visible curds will stay noticeable in a sauce that starts out lumpy.

5. Remove roasted squash and reduce oven temperature to 375°F (190°C). In a large bowl, gently combine chicken, drained beans, onion and kale mixture with its reduced cider, blended sauce, and ½ cup grated cheddar.

Fold in squash last, using a wide spoon or spatula so those browned cubes keep their shape. Everything should look generously coated, with sauce settling between ingredients

Resist stirring until squash breaks down, because those soft, distinct pieces are part of what makes each bite so good. Keep this mixture off direct stovetop heat to avoid boiling your dairy sauce before baking.

6. Spoon filling into your greased baking dish and spread it evenly, leaving at least ½ inch of space beneath the rim. Sprinkle remaining ¼ cup cheddar across the surface, then toss panko and pepitas with ½ tablespoon olive oil until crumbs look lightly moistened.

Scatter this mixture evenly over cheese, reaching right into the corners. Spread crumbs loosely rather than pressing them down, which helps exposed bits turn crisp.

I would be particularly fair about those corners, because someone at your table is almost certainly monitoring the crunchy-piece distribution!

7. Bake uncovered at 375°F for 35 to 40 minutes, until topping is golden, sauce bubbles gently around the edges, and an instant-read thermometer registers 165°F (74°C) in the center.

Check a couple of central spots without touching the bottom of the dish. A casserole assembled with very cold ingredients may need another 5 to 10 minutes, so let temperature guide you.

If crumbs brown before filling is hot, loosely cover with foil and continue baking. Pepitas can go from toasted to bitter quickly under a broiler, so I would let ordinary oven heat do the finishing here. 

8. Let your casserole rest for 10 minutes before serving, giving sauce time to settle around chicken and beans instead of rushing straight into the space where you scooped. Divide into six equal portions, taking a little topping with each spoonful.

Expect a creamy, spoonable casserole rather than firm slices, with tender squash, juicy pieces of chicken, and little bursts of toasted pumpkin seed. That short rest also makes your first bite much friendlier to the roof of your mouth!

Serving Suggestions!

This casserole already brings chicken, beans, vegetables, and a creamy sauce to dinner, so I would keep anything alongside it bright and simple.

• For a fresh contrast: Serve with arugula, thinly sliced radishes, and cucumber tossed with lemon juice and olive oil. Peppery leaves and crisp vegetables work beautifully beside warm cheddar and sweet squash.
• For an extra vegetable: Add steamed green beans with lemon zest and black pepper, or quickly sautéed broccoli with a squeeze of lemon.
• For bigger appetites: Offer a small slice of toasted sourdough for catching any creamy sauce left on the plate. A clean plate is a perfectly reasonable dinner ambition!

Make Ahead and Store Leftovers

• To prepare a day ahead, roast squash and cook onion mixture, then refrigerate them promptly in shallow containers.
• Keep chicken and blended sauce refrigerated separately, and mix dry panko with pepitas in a covered container without adding oil.
• Assemble within 24 hours, add cheese and freshly oiled topping, and bake at 375°F, allowing approximately 45 to 55 minutes for a cold filling to reach 165°F.
• Use a pan suitable for going from refrigerator temperature into a hot oven, and cover loosely if topping colors too quickly.
• Refrigerate cooked leftovers in shallow airtight containers within 2 hours, or within 1 hour if surrounding temperature is above 90°F.
• Keep refrigerated at 40°F or below and use within 3 to 4 days; if you started with older leftover chicken, plan around its remaining storage time.
• For longer storage, freeze individual portions for up to 2 months for best texture, then thaw overnight in your refrigerator.
• Cottage cheese sauce may become slightly less smooth after freezing, and topping will soften.
• Reheat a refrigerated portion in an oven-safe dish at 350°F (175°C), loosely covered, for about 20 to 30 minutes, adding a tablespoon of broth if filling looks dry.
• Uncover toward the end to help crumbs crisp, and check that your portion reaches 165°F throughout.
• For a quicker lunch, microwave a covered portion in short intervals, rotating and checking several spots until evenly hot; microwave power and portion size will affect timing. 

A Few Small Choices That Matter!

• Use cooked chicken weight. One pound of raw chicken will weigh less after cooking, so measuring 450 g of already-cooked meat helps keep both portions and protein estimates consistent. Nutrition estimates assume six equal servings, skinless chicken breast, 2% cottage cheese, and all listed topping ingredients.
• Drain beans thoroughly. Leave rinsed beans in a colander while you chop onion. Extra water clinging to beans is easy to overlook, especially when you have already measured broth carefully.
• Keep cider and vinegar separate. Drinking cider gives your onion mixture a mellow apple flavor, while just 1 teaspoon of cider vinegar brightens sauce. Unsweetened apple juice can replace drinking cider in an equal amount; ½ cup vinegar cannot!
• Choose squash by weight. Peeled, seeded squash is what counts toward 1½ pounds. If buying a whole squash, choose one around 2 to 2½ pounds to allow for peel, seeds, and trimming.

Bring this high protein harvest casserole to your table while its cheddar topping is still golden and fragrant, then spoon down into creamy chicken, sweet roasted squash, and tender white beans.

With tangy cider Dijon sauce tucked into every bite and a little pepita crunch on top, it gives a simple casserole dinner plenty of personality.

Save yourself a portion before everyone starts negotiating over those crispy corners!