Preheat the oven to 425 degrees F.
Heat 2 tablespoons of olive oil in a sauté pan over medium high heat. Add in the minced garlic and carrots. Season with salt and pepper. Sauté carrots until tender about 5 minutes.
Meanwhile, chop the chicken; season with salt, pepper, and garlic powder. Set aside.
Once the carrots are tender, add in the onions, bell peppers, and mushrooms. Sauté until vegetables are tender 5-7 minutes. Season with salt and pepper; set aside.
In a large sauce pan add the butter and flour and mix well until a light brown roux has formed. Add in milk and chicken stock and mix to combine. Bring the mixture to a boil, add salt and pepper, reduce heat to a simmer; let thicken.
While the mixture is thickening, make the chicken. Add one tablespoon of olive oil to a sauté pan over medium heat. Add in chopped chicken and cook until chicken is browed about 7 minutes.
Add chicken, vegetables, and peas into the sauce; stir to combine. Leave heat on low until the mixture is ready to go into the prepared mason jars.
Break off small pieces of crust and press it into the bottom and up the sides of your mason jars. Add in the chicken mixture to each prepared mason jar leaving about an inch empty at the top. Roll your remaining dough into pieces large enough to cover the tops of your mason jar. Add prepared tops to each mason jar.
Bake at 425 degrees for 15-20 minutes until the tops of the dough are browned.