Air fryer chicken pot pie 3 ways

Name: Air fryer chicken pot pie 3 ways
Cuisine: American
Ingredients: 4 boneless chicken thighs; 1 large brown onion, chopped; 2 carrots, diced; 2 sticks of celery, diced; 4 cloves of garlic, chopped; 40g Butter; 3 tbsp garlic oil; 4tbsp cornstarch; 1/2 cup milk; 2 tsp marmite; 1 chicken stock cube; 2 tsp dried thyme; 1/2 cup frozen peas; 1 pinch Freshly ground nutmeg; Salt to taste; Freshly ground black pepper to taste; MSG to taste; 4 potatoes; 100g butter; 1 egg, large; Salt to taste; White pepper to taste; 3potatoes; 15g butter; 1tsp grated Parmesan cheese; Plain flour; Vegetable oil; Water; Salt