Step 1

Prepare grill for medium-high heat. Toss brussels sprouts and oil in a medium bowl; season with salt and pepper. Transfer brussels sprouts to a grill basket and grill, tossing occasionally, until tender and lightly charred, 5–8 minutes. (Alternatively, cook brussels sprouts in a large grill pan or skillet over medium-high heat, 5–8 minutes.)

Step 2

Cook bacon in a large skillet over medium-low heat, stirring occasionally, until crisp, 5–8 minutes. Transfer to a paper towel–lined plate.

Step 3

Add mushrooms to drippings in skillet, toss to coat, and cook without stirring, 3 minutes. Add shallot and garlic; cook, tossing often, until shallot is softened, about 5 minutes. Remove from heat and add Sherry and red pepper flakes. Cook until liquid is evaporated, about 1 minute. Add brussels sprouts and bacon and toss to combine. Add lemon juice; season with salt and pepper.