Heat a stock pot over medium heat with 2 tbs butter and 1 tbs olive oil. When the butter is melted and oil is warm, add chopped onions, carrots, celery, and potatoes. Season with salt and pepper. Cook about 2 minutes, until the veggies begin to sweat or just barely soften. Add the cut chicken breast and garlic. Season with salt, pepper, and 1 tsp of a poultry seasoning. Cook until the chicken is golden on the outside and cooked through on the inside, about 5 minutes per side. Stir frequently. Stir in 6 tbs flour and keep stirring until the liquid released by the veggies and chicken reaches a paste like consistency. Stir in the chicken stock. Bring to a slow simmer and let simmer for about 15 minutes. Stir in the frozen veggies. Bring back to a slow simmer and allow to simmer for 3-5 minutes. Stir in the half and half and cook another 2 minutes until the soup is warmed through. Serve and enjoy.