Heat the oven to 425 degrees.

Cut small to medium brussels sprouts in half and cut large ones in quarters; place on a sheet pan. Cut the shallots into rings; place on the same sheet pan. Season the vegetables lightly with salt and pepper and toss.

Add the bacon to the sheet pan and separate any pieces that have stuck together. Toss with the sprouts and shallots then arrange in an even layer. Roast, tossing sprouts and rotating pan once, until the vegetables are cooked through with caramelized edges and the bacon is lightly browned and crisp, 25 to 30 minutes (see Tip).

While the sprouts cook, cut the lemon in half, finely chop the garlic and set both aside.

When the sprouts come out of the oven and are still hot, add the garlic and juice from one lemon half, then sprinkle with red pepper to taste and toss to combine. Add the herbs, if using, and toss again. Serve warm.