In a mixing bowl, combine flour and salt, then cut in cold, cubed butter until coarse. Gradually add ice water until the dough forms. Shape into a disk, wrap, and chill for at least 30 minutes.

In a skillet, heat olive oil over medium-high heat and sauté seasoned chicken thighs for 6-8 minutes per side until golden brown. Remove from skillet, cool slightly, and cut into bite-sized pieces.

In the same skillet, add more olive oil if needed, then add chopped onions, diced carrots, and mushrooms. Cook for 5-7 minutes until softened. Stir in minced garlic and cook for another minute.

Sprinkle flour over sautéed vegetables, stirring well, then gradually whisk in chicken broth. Allow to thicken for 3-5 minutes, then add heavy cream, thyme, rosemary, and cooked chicken, followed by peas.

Roll out the chilled crust, transfer filling into the crust, cover with top crust, seal edges, and cut slits in the top to allow steam to escape.

Preheat oven to 425°F. Bake pot pie for 25-30 minutes until the crust is golden-brown and filling is bubbling.

Remove pot pie and let cool for 15-20 minutes before serving to set the filling.