This high-protein chicken pot pie casserole delivers cozy comfort in a fraction of the time. Packed with chicken, vegetables, and a creamy sauce topped with a golden crust.

Ingredients

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Instructions

Step 1

Preheat your oven to 400°F (200°C). Position a rack in the center of the oven to ensure even baking. While the oven heats, prepare all your ingredients: dice the onion, mince the garlic, peel and dice the carrots, and dice the celery. Cut the chicken breasts into uniform bite-sized pieces—about 1-inch cubes—so they cook evenly. Having everything prepped and ready (mise en place) will make the cooking process smooth and prevent any scrambling later.

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Step 2

In a large oven-safe skillet or Dutch oven (at least 12 inches in diameter), heat the olive oil over medium-high heat until it shimmers. Add the diced onion, carrots, and celery. Sauté for 5-7 minutes, stirring occasionally, until the vegetables begin to soften and the onion turns translucent. The aroma should be sweet and savory. Add the minced garlic and cook for 1 more minute, until fragrant. Be careful not to burn the garlic, as it can turn bitter.

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Step 3

Add the chicken pieces to the skillet in a single layer. Season with dried thyme, dried rosemary, paprika, salt, and black pepper. Cook for 5-6 minutes, stirring occasionally, until the chicken is browned on all sides but not cooked through. The chicken will finish cooking in the oven. This browning step is crucial for developing deep flavor through the Maillard reaction.

Step 4

Sprinkle the flour evenly over the chicken and vegetables. Stir constantly for 1-2 minutes to cook the flour and eliminate the raw taste. The mixture will become pasty and coat everything. This roux will thicken the sauce later.

Step 5

Slowly pour in the chicken broth while stirring continuously to prevent lumps. Then add the milk and heavy cream (if using). Bring the mixture to a gentle simmer—you’ll see small bubbles around the edges. Let it cook for 3-4 minutes, stirring occasionally, until the sauce thickens enough to coat the back of a spoon. Taste and adjust seasoning with more salt and pepper if needed. Stir in the frozen peas. Remove the skillet from heat.

Step 6

If using puff pastry, gently unfold the thawed sheet on a lightly floured surface. Roll it out slightly to fit the top of your skillet or baking dish. You can also cut decorative vents or shapes for steam to escape. Carefully lay the pastry over the filling, tucking the edges under or pressing them against the rim of the skillet. If using a pie crust, roll it out and crimp the edges decoratively. Brush the top with the beaten egg wash for a shiny, golden finish.

Step 7

Place the skillet in the preheated oven and bake for 20-25 minutes, until the pastry is puffed and golden brown and the filling is bubbling around the edges. If the pastry browns too quickly, tent loosely with foil during the last 5 minutes. Let the casserole rest for 5-10 minutes before serving. This allows the filling to set slightly and prevents burns. Serve warm, garnished with fresh parsley if desired.

For best results

  • For the best texture, avoid overcooking the chicken during the stovetop step. Since the casserole will bake in the oven, the chicken will continue to cook and remain juicy. Overcooking on the stovetop can lead to dry, tough meat. Aim for just-browned pieces with a little pink inside; they'll finish perfectly in the oven.
  • To make the casserole gluten-free, substitute the all-purpose flour with a 1:1 gluten-free flour blend or cornstarch. If using cornstarch, mix 2 tablespoons with 3 tablespoons cold water to form a slurry, then stir it into the simmering liquid. Note that gluten-free flours may not thicken as much, so simmer a minute longer.
  • The puff pastry can be replaced with a variety of toppings: buttermilk biscuits (cut into rounds and placed on top), crescent roll dough, or even a mashed potato topping for a shepherd's pie twist. Each option changes the texture and flavor profile, so choose based on your preference and dietary needs.
  • Store leftovers in an airtight container in the refrigerator for up to 4 days. The pastry may lose its crispness upon reheating; to revive it, reheat individual portions in a 350°F oven for 10 minutes or in an air fryer at 350°F for 5 minutes. Avoid microwaving, as it makes the pastry soggy.
  • To freeze the unbaked casserole, assemble it completely but do not add the pastry topping. Cover tightly with plastic wrap and foil, then freeze for up to 3 months. When ready to bake, thaw in the refrigerator overnight, add the pastry, and bake as directed, adding 10-15 minutes to the baking time since the filling will be cold.
  • For a dairy-free version, replace the milk with unsweetened oat milk or cashew milk, and use a dairy-free heavy cream alternative (like coconut cream). The sauce will be slightly thinner but still delicious. Use a vegan puff pastry (most brands are dairy-free) to keep it entirely plant-based.

Variations

  • Vegetarian / Plant-Based: Swap the chicken for 2 cans of drained chickpeas or 2 cups of diced extra-firm tofu (pressed and pan-fried for texture). Use vegetable broth instead of chicken broth. The cooking time remains the same. For an extra protein boost, add 1 cup of cooked lentils along with the peas.
  • Low-Carb / Keto: Omit the flour and thicken the sauce with 2 tablespoons of cream cheese or 1 teaspoon of xanthan gum blended into the broth. Replace the puff pastry with a low-carb topping made from almond flour and cheese (e.g., 1 cup almond flour, 1 cup shredded mozzarella, 1 egg, rolled out and baked). Bake as directed.
  • Spicy Southwest: Add 1 diced jalapeño (seeds removed for less heat) with the onions, and stir in 1 teaspoon cumin and 1/2 teaspoon chili powder. Replace peas with 1 cup frozen corn and 1 can drained black beans. Top with a cornbread crust instead of puff pastry for a Tex-Mex twist.
  • Creamy Mushroom: Replace the chicken with 3 cups of sliced cremini or portobello mushrooms. Sauté them with the vegetables until golden brown. Use a mix of mushroom broth and heavy cream for an earthy, umami-rich filling. The mushrooms provide a meaty texture and are naturally low in calories.

Nutrition

  • Calories485 kcal
  • Total Fat24g
  • Saturated Fat10g
  • Cholesterol115mg
  • Sodium620mg
  • Total Carbohydrates32g
  • Dietary Fiber4g
  • Sugars6g
  • Protein35g

Common Questions

Can I use leftover rotisserie chicken instead of raw chicken?
Absolutely! Using pre-cooked chicken is a fantastic time-saver. Simply shred or chop the rotisserie chicken and add it to the skillet after you’ve made the sauce, just before adding the peas. Since the chicken is already cooked, you only need to heat it through. Skip the stovetop browning step for the chicken, and reduce the baking time by 5-10 minutes to avoid drying out the meat.
How do I prevent the bottom crust from getting soggy?
Since this recipe uses a top crust only (puff pastry or pie crust), sogginess is less of an issue. However, to ensure the pastry stays crisp, make sure the filling is hot when you place the pastry on top. The hot filling creates steam that helps the pastry rise and cook quickly. Also, avoid overloading the filling with too much liquid; the sauce should be thick enough to coat a spoon, not soupy.
Can I make this casserole in advance?
Yes! You can prepare the filling up to 2 days ahead and store it in the refrigerator. When ready to bake, reheat the filling on the stovetop until bubbling, then transfer to a baking dish, top with pastry, and bake as directed. Alternatively, assemble the entire casserole (without baking) and refrigerate for up to 24 hours. Add 5-10 minutes to the baking time if starting from cold.
What can I use instead of puff pastry?
Many alternatives work beautifully: refrigerated biscuit dough (cut into rounds and placed on top), crescent roll dough (perforated sheets), a traditional double pie crust (for a top and bottom crust), or even a layer of mashed potatoes for a shepherd’s pie feel. For a gluten-free option, use a gluten-free pie crust or a topping of crushed pork rinds mixed with cheese for a keto-friendly crisp.
Is this recipe freezer-friendly?
Yes, but with a slight modification. For best results, freeze the filling without the pastry topping. Cool the filling completely, then transfer to a freezer-safe container or baking dish. Cover tightly and freeze for up to 3 months. When ready to enjoy, thaw overnight in the refrigerator, reheat on the stovetop or in the microwave until hot, then transfer to a baking dish, add the pastry, and bake as directed.
How can I increase the protein content further?
To boost protein, you can add 1 cup of cooked quinoa or 1/2 cup of unflavored protein powder (whey or plant-based) stirred into the sauce after removing from heat. Another option is to mix in 1 cup of cottage cheese or Greek yogurt at the end for a creamy, protein-rich sauce (add off heat to avoid curdling). You can also top with shredded cheese before adding the pastry.
Can I use frozen mixed vegetables instead of fresh?
Definitely! Frozen mixed vegetables (peas, carrots, corn, green beans) are a convenient and nutritious option. Add them frozen directly to the sauce; they will thaw and heat through during the simmering and baking. No need to thaw first. Just be aware that frozen vegetables release more water, so you may need to simmer the sauce a minute or two longer to thicken.
What's the best way to reheat leftovers?
The oven or air fryer yields the best results for maintaining crisp pastry. Preheat to 350°F (175°C), place individual portions on a baking sheet, and heat for 10-12 minutes (oven) or 5-7 minutes (air fryer). If using a microwave, the pastry will become soft, but the filling will be hot. To minimize sogginess, microwave the filling separately and reheat the pastry in a toaster oven.