Make the glaze. In a small bowl, whisk together the miso paste, honey, vinegar, and dijon until smooth. Set aside.
Preheat an oven to 450 F.
Cook the bacon. Heat a large cast iron skillet or braiser (12-13”) over medium low heat. Add the bacon and cook, stirring occasionally, until crispy and the fat is rendered. Use a slotted spoon to transfer the bacon to a small dish. Discard all but 1 tablespoon of the bacon fat.
Sear the brussels sprouts. Increase the heat to medium-high and once the pan and bacon fat are hot, add the brussels sprouts to the pan, tossing them to coat in the fat. Sprinkle the sprouts with salt and pepper and cook for 2 minutes, undisturbed. Add the shallots to the pan and toss everything together. Continue to cook for 3-4 minutes more, until the brussels are browned in places and the shallots are soft.
Bake and glaze the brussels. Transfer the pan to the oven for 5 minutes. Remove the pan from the oven and toss the brussels with the honey-miso mixture and the bacon. Return to the oven for 5 minutes, then broil on high for 1 minute.
Remove the pan from the oven and transfer the brussels to a serving bowl. Top with the freshly grated parmesan and serve right away.