Fill a large pot with enough water to fully submerge the Brussels sprouts, and place over high heat. Bring the water to a boil and season with the kosher salt. Add the Brussels sprouts to the boiling water and stir. Boil for 4-5 minutes until tender but still bright green. Drain in a colander, run under cold water to stop the cooking process, then lay on a kitchen towel to dry.

Place the bacon in a 12" skillet and heat over medium heat. Saute, stirring occasionally, until the fat renders and the bacon is crisp, about 7-8 minutes. Remove the bacon with a slotted spoon and place on a paper towel-lined plate to drain.

Increase the heat to medium high, add the blanched Brussels sprouts and pecans to the rendered bacon fat. Saute over high heat, stirring frequently until the sprouts are crisp, about 4-5 minutes.

Sprinkle the mustard powder over the sprouts and pecans, then stir constantly for 1 minute. Pour the bourbon or cider vinegar into the pan to deglaze; stir and scrape constantly until browned bits are scraped up and the bourbon is absorbed, about 2-3 minutes.

Add the bacon back to the pan, then pour in the maple syrup. Toss everything together, then cook for 1 minute more until the syrup is slightly thickened. Taste for seasoning and adjust with salt and pepper if needed. Serve right away and enjoy!