Trim ends of Brussels sprouts and finely slice. Rinse Brussels sprouts in a colander and pat dry.
In large nonstick skillet, cook bacon over medium heat for 4 to 6 minutes or til crispy. Put bacon on paper towels to drain. Crumble bacon. Drain grease form pan, reserving 3 Tbsp.
Core apple, and slice into bite size pieces. In small bowl whisk together brown sugar, vinegar, salt and pepper. Heat reserved bacon drippings in skillet over medium high heat. Add Brussels sprouts and cook for 3 to 4 minutes or til the begin to brown slightly. Stir often. Add apple to skillet, stirring to mix. Cook for 1 minute
Pour brown sugar mixture over sprouts mixture. Cook for 1 minute or til sugar has dissolved. Stir often. Add bacon and stir to mix.