Cook the bacon until crisp in a large skillet. Remove with a slotted spoon to a plate.
While the bacon is cooking, cut off the ends of the brussels sprouts. Then chop the Brussels sprouts in half. Lay them cut-side-down and finely chop until they are all shredded.
Add the garlic and shallots to the skillet and saute until fragrant and the shallots are soft, 1 to 2 minutes. Stir in the Brussels sprouts and saute until tender crisp, 3 to 5 minutes. Add a pinch of brown sugar. Season with salt and pepper and add the lemon juice. Saute for 1 minute more. Toss with the chopped parsley and bacon. Serve hot or at room temperature.