Season the steaks on both sides with salt and pepper. In a small bowl, mix together the garlic and all but 2 teaspoons of the mustard. Place the steaks on a plate, and spread half of the garlic mustard mixture over one side of them. Let stand for 30 minutes.
Heat a large skillet over medium-high heat. Fry bacon until crisp, then remove from the pan, leaving the grease. Crumble the bacon and set aside.
Heat the bacon grease in the skillet over medium-high heat, and add olive oil if necessary to cover the bottom of the pan. Fry steaks mustard side down for about 5 minutes, until golden brown. While the steaks are frying, spread the remaining garlic and mustard over the top. Flip the steaks over, and fry for about 2 minutes, until browned. Remove steaks to a serving platter, and keep warm.
Keep the skillet over medium-high heat, and stir in the rosemary, whiskey, reserved mustard, Worcestershire sauce, brown sugar, and lemon juice. Simmer for about 2 minutes. Top steaks with crumbled bacon and the sauce, and serve.