1. Preheat oven to 350°F. Cook bacon in a large skillet over medium heat, stirring often, until crisp, 12 to 14 minutes. Transfer to a paper towel-lined plate to drain. Remove and discard all but 3 Tbsp. bacon fat from skillet.
2. Raise heat to medium-high. Add sprouts to bacon fat in skillet and cook, stirring occasionally, until just beginning to soften, 5 to 7 minutes. Add red pepper, lemon zest and reserved bacon to skillet. Stir, taste and season with salt and pepper. Remove from heat.
3. Brush both sides of baguette slices with olive oil; place on a baking sheet. Bake until golden, 5 to 6 minutes per side.
4. Spoon a rounded Tbsp. of sprout mixture on each slice of baguette. Top each with a slice of cheese and serve.