Heat oven to 425 degrees Fahrenheit. Line a large baking sheet with parchment paper. Place bacon on parchment paper, making sure to space evenly, and bake for 15 minutes or until bacon has reached desired crispness. Using metal tongs, carefully remove hot bacon from baking sheet and place on a paper towel to absorb excess oil. Set aside.
In a small bowl, whisk together maple syrup and vinegar.
Reduce oven heat to 400 degrees Fahrenheit. Using the same baking sheet and parchment paper from the bacon, place quartered Brussels Sprouts on baking sheet. Drizzle with syrup mixture and toss lightly to coat evenly with bacon grease and syrup.
Roast for 20 to 25 minutes, or until sprouts are beginning to crisp on the outside but are still tender on the inside. Stir occasionally in the oven for more even browning.
Coarsely chop cooked bacon. Toss bacon and toasted pecans with roasted sprouts and serve immediately.