Cook the Chicken:
In a large pot, melt 1 tablespoon of butter over medium heat. Add the diced chicken and season with salt and pepper. Cook the chicken until browned and cooked through (about 5-7 minutes). Remove the chicken from the pot and set aside.

Sauté Vegetables:
In the same pot, melt the remaining tablespoon of butter. Add the diced onion, carrots, and celery. Sauté until the vegetables start to soften (about 5 minutes). Add the minced garlic and cook for another minute until fragrant.

Make the Roux:
Sprinkle the flour over the sautéed vegetables and stir to combine. Cook for 2-3 minutes to remove the raw flour taste, stirring frequently. This will help thicken the soup.

Add Liquids:
Slowly pour in the chicken broth while whisking to avoid lumps. Stir in the half-and-half (or heavy cream) and bring the soup to a simmer. Let it cook for 10 minutes, or until the soup thickens slightly.

Add Chicken and Vegetables:
Return the cooked chicken to the pot and add the frozen peas and corn (if using). Stir to combine and cook for an additional 5 minutes to heat everything through.

Season and Finish:
Stir in the dried thyme, parsley, salt, and pepper to taste. If desired, add grated Parmesan cheese for extra creaminess and flavor. Simmer the soup for another 5 minutes.

Optional Biscuit/Pastry Topping:
If you’d like to add a biscuit or pastry topping, prepare your pre-made biscuit dough or puff pastry according to the package directions. Bake them separately and place them on top of the soup just before serving.

Serve:
Ladle the soup into bowls and garnish with fresh parsley. Serve with biscuit topping or crusty bread on the side for an extra comforting touch.