Trim only the bottom of each brussels sprout stem, then slice the sprouts in half and set them aside.

Blend the orange juice, shallot, olive oil, mustard, vinegar, maple syrup, and salt in a food processor until the sauce is smooth. Taste and adjust the flavors if desired, then set the sauce aside.

Cook the bacon according to package directions until crispy. Transfer it to paper towels to drain, then chop it into small pieces once cool enough to handle. Reserve the hot bacon grease in a heatproof container.

Place the same pan over medium-high heat and arrange the brussels sprouts cut side down. Drizzle with 1-2 teaspoons of the reserved bacon grease and gently move the sprouts as needed while keeping the cut sides facing the pan.

After about five minutes, once the cut sides have browned slightly and the pan is hot, pour the sauce into the pan with the brussels sprouts. Shake the pan by the handle(s) to move the sprouts around and cook for 1 minute or less until the desired caramelization is reached. Remove from heat.

Toss the brussels sprouts with the reserved bacon pieces and Parmesan cheese.