01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large mixing bowl, whisk together maple syrup, Dijon mustard, olive oil, apple cider vinegar, sea salt, and black pepper until the mixture is thoroughly emulsified.
03 - Add the trimmed and halved Brussels sprouts to the bowl and gently toss until each piece is evenly coated with the glaze.
04 - Distribute the glazed Brussels sprouts cut side down in a single layer on the prepared baking sheet for optimal browning.
05 - Roast for 20 to 25 minutes, stirring halfway through, until the Brussels sprouts develop a golden, caramelized finish and crisp edges.
06 - Transfer the roasted Brussels sprouts to a serving dish. Garnish with chopped toasted pecans and fresh parsley if desired. Serve immediately while hot.