Blanch the Brussels sprouts in a large pot of boiling salted water for 4-5 minutes until bright green and tender, then drain and plunge into an ice bath.

Cook diced bacon in a large skillet over medium heat for 7-8 minutes until crispy. Remove with a slotted spoon and let drain on paper towels, retaining the bacon fat in the skillet.

Sauté the blanched Brussels sprouts and chopped pecans in the bacon fat over medium-high heat for 4-5 minutes until golden and crisp around the edges.

Sprinkle ground mustard over the sprouts and pecans, deglaze with bourbon or apple cider vinegar, and cook for 2-3 minutes until the liquid reduces.

Combine the crispy bacon with the sautéed mixture, add maple syrup, and cook for an additional minute until thickened. Adjust seasoning with salt and pepper to taste.