DISSOLVE 1 teaspoon coffee crystals in balsamic vinegar. Add oil, roasted garlic, salt and pepper. Rub over all sides of beef medallions.
HEAT butter shortening in large skillet over medium high heat. Sear beef 3 to 4 minutes per side for medium rare or to desired doneness. Transfer to plate, cover and keep warm. Saute mushrooms in skillet until lightly browned.
WHISK remaining 1/4 teaspoon coffee crystals and broth in small bowl until dissolved. Add heavy cream and balsamic vinegar, brown sugar and Worcestershire sauce. Pour cream mixture into skillet with mushrooms. Bring to a boil over high heat, stirring constantly, until sauce just begins to thicken. Serve steaks drizzled with sauce. Garnish with cracked black pepper, if desired.