Pound chicken breast between plastic wrap to 1/4-1/2 inch thick. Cut chicken into 8 cutlets. Pat dry and salt and pepper. In a skillet heat butter and olive oil to medium heat.
Combine the flour and the paprika in a pie plate or med bowl. Dredge chicken cutlets in flour and brown them 3-4 minutes per side. Remove from skillet.
Add the garlic and scallion to the skillet, and saute until fragrant about 30 seconds.On med-high heat Pour in the chicken broth, white wine, 1 Tbs lemon juice, tarragon and lemon zest. Simmer for about 5 minutes.
Add the chicken cutlets back to the skillet, cover, and simmer for about 10 minutes, or until chicken is cooked through. At this point taste to see if you want to add more lemon juice, and cook for 1 minute longer.
Plate and sprinkle the parmesan-reggiano over the chicken