In medium-size saucepan, heat butter over medium heat. Add shallot; sauté for 2 minutes or until softened. Add wine and thyme; simmer over medium heat 5 minutes. Stir in cream and mustard. Bring to a simmer; cook for 15 minutes or until reduced to about 1 cup. Add salt. Strain sauce; keep warm.
While sauce is cooking, heat oven to 400°F. In small bowl, mix together crushed peppercorns, salt and 2 teaspoons vegetable oil. Rub the mixture over both sides of steaks.
In a large cast-iron skillet, heat the remaining 2 tablespoons vegetable oil over medium-high heat. Add steaks; cook 2 minutes per side.
Place the skillet in 400°F oven. Cook for 5 minutes or until the internal temperature registers 140°F on an instant-read meat thermometer. Transfer steaks to warm platter. Let stand 5 minutes (temperature will increase to 145°F).
Serve steaks with sauce on the side, with rice, if desired.