Firstly, cook the chicken breasts using your preferred method: baking, poaching, or grilling. Once cooked, shred the chicken into bite-sized pieces and set aside.

Heat olive oil and butter in a large pot or Dutch oven over medium heat. Add the diced carrots, celery, and onion. Sauté until the vegetables are softened, about 5-7 minutes.

Add the sliced mushrooms to the pot and cook for another 3-5 minutes, until they release their moisture and soften. Stir in the dried thyme, dried rosemary, salt, pepper, and garlic powder. Cook for an additional minute to allow the spices to bloom.

Sprinkle the flour over the vegetables and stir to coat. Cook for 1-2 minutes to cook out the raw flour taste. Gradually whisk in the low-sodium chicken broth, ensuring there are no lumps. Bring the mixture to a simmer, stirring occasionally.

Reduce the heat to low and simmer for 5-10 minutes, or until the sauce has thickened to your desired consistency. Stir in the almond milk (or milk alternative) and heat through.

Add the shredded chicken, frozen peas, and frozen corn to the pot. Stir to combine all ingredients and ensure everything is heated through.

Preheat your oven to 375°F (190°C). If using a refrigerated pie crust, unroll it and place it over the pot pie filling in a baking dish or individual ramekins. Cut slits in the crust to allow steam to escape. Alternatively, if using cauliflower mash, spread it evenly over the filling.

Bake for 20-25 minutes, or until the crust is golden brown and the filling is bubbly. If the crust starts to brown too quickly, cover it loosely with foil.

Remove the pot pie from the oven and let it cool for a few minutes before serving. This allows the filling to set slightly and prevents burning your mouth. Enjoy your delicious and healthy chicken pot pie!