Melt butter with oil in a large skillet over medium-high heat; add fillets, and cook 5 minutes on each side or to desired degree of doneness. Remove fillets, and keep warm.
Add pear halves to skillet; cook over medium heat 5 minutes on each side or until browned. Add wine, garlic, and thyme; cook 5 minutes or until pear halves are tender. Remove pear halves from skillet, reserving wine mixture in skillet.
Cook wine mixture in skillet over high heat 7 to 8 minutes or until mixture is reduced by half.
Stuff each pear half evenly with blue cheese. Serve with fillets, and drizzle with sauce.