Sprinkle sole fillets with 1/4 teaspoon salt and 1/8 teaspoon pepper. Roll up, starting with small end. Secure with wooden picks. Set aside.
Combine white wine and next 4 ingredients in a large skillet. Add rolled up fish; bring to a simmer over medium heat. Cover, reduce heat to low, and simmer 5 minutes. Remove fillets with a slotted spoon; set aside, and keep warm.
Increase heat to high, and cook wine mixture 5 minutes or until most of liquid is absorbed. Combine half-and-half and cornstarch, stirring well with a whisk. Add to mixture in skillet. Cook 2 minutes or until thickened, stirring constantly. Remove from heat; add sour cream, remaining 1/4 teaspoon salt, and 1/8 teaspoon pepper, stirring until thoroughly combined. Strain mixture through a sieve over a bowl; discard solids. Stir 1 teaspoon tarragon into sauce. Pour sauce over fish. Garnish with tarragon leaves, if desired.