PREHEAT oven to 400° F.
TOSS brussels sprouts with olive oil, salt and pepper. Spread out on cookie sheet and roast in oven, tossing occasionally, for 8-10 minutes until lightly browned.
COOK bacon in a large skillet over medium heat, turning occasionally until crisp, about 5-8 minutes. Remove from pan and reserve bacon drippings.
PREPARE tortellini according to package directions. Drain and reserve 2 tablespoons of the pasta water.
ADD garlic to skillet with bacon drippings, and sauté over medium heat until almost browned.
ADD roasted brussels sprouts and chopped bacon to the pan and turn heat to low.
ADD tortellini, pasta water, and pesto to pan. Toss to coat.