In a small bowl, whisk together miso paste, Dijon mustard, rice vinegar, sesame oil, soy sauce, and chili flakes. Slowly stir the oil in and set aside.
Heat 2 tbsp olive oil in a large skillet over medium-high heat. Once heated, sauté the brussel sprouts for 7 to 8 minutes, stirring occasionally until tender.
While the brussel sprouts cook, combine panko breadcrumbs, parmesan, and sesame seeds in a small bowl and toss to combine.
Pour miso-sesame mixture into skillet with Brussels sprouts and toss to coat.
Remove from heat, place in a bowl or on a platter, and top with the panko, parmesan mixture.