Trim stems and remove outer leaves from Brussels sprouts; wash, then cut larger sprouts in half. In a covered pot, boil Brussels sprouts with enough water to cover until tender. Approximately 8-10 minutes.
In a large skillet, cook prosciutto in hot oil over medium heat; once crispy, remove. Use same pan and oil to cook shallots, garlic and butter. Allow to soften, then add sprouts, salt and pepper.
Cook for approximately 8 minutes or until browned. Drizzle with Balsamic vinegar. Sprinkle with prosciutto.