Boil: Preheat oven to 375°F. In a large saucepan, combine potatoes, carrots, and peas with the chicken broth. Boil for 10–15 minutes until potatoes are fork tender, then drain and set aside.
Pot Pie: In a large saucepan over medium heat, heat the olive oil until shimmering. Add onions and cook for 2–3 minutes, then add garlic and cook for 30 seconds. Add celery and cook until soft and translucent. Transfer this mixture right on top of the other veggies.
Return the saucepan to heat and melt the butter. Whisk in the flour and cook until the mixture turns light brown, about 3–4 minutes. Season with salt, pepper, celery seed, Italian seasoning, thyme, and parsley. Gradually add chicken stock and milk, simmering on medium-low until the sauce thickens. Adjust thickness by adding more stock and milk if desired. Mix in corn and ham with the other veggies, then pour the sauce over and stir until combined. Adjust seasonings to taste.
Place one pie crust in a 9-inch, deep-dish pie pan and brush lightly with egg whites. Prebake for 5 minutes, then add the sauce and veggie mix. Cover with second crust, seal edges, and cut slits in the top. Brush with egg whites and bake for 35–40 minutes or until golden brown.
Serve if desired with fresh thyme/and or parsley.
Notes
Note 1: I leave the skin on the potatoes, but make sure to rinse them beforehand. If you prefer, you can peel them before use.Storage: Store in an airtight container in the fridge for up to 3–4 days. To freeze, wrap it tightly in plastic wrap or foil and freeze for up to 3 months. Thaw in the fridge overnight before reheating.