Melt butter in a pan and sauté chopped onion, celery, and carrots for 5 minutes
Add minced garlic and flour, cook until flour is incorporated
Add celery salt, onion powder, garlic powder, and rosemary
Slowly pour in chicken stock and milk, stirring until thickened
Add heavy cream and whole grain mustard
Stir in frozen peas and shredded chicken
Cook gnocchi separately until it floats to the top
Transfer chicken pot pie filling to a baking dish
Top with cooked gnocchi, drizzle with olive oil, and sprinkle with parmesan
Bake at 350°F for about 25 minutes
Optional: finish under the broiler for a few minutes to get extra golden on top
