This is perfect served warm or at room temperature. Crostini can be made 8 hours in advance and just stored lightly covered at room temperature. You can pop in the oven for 2 minutes just to reheat or crisp up, if needed just before serving. Bacon can be made several hours in advance.
Use parchment paper on your baking sheets for easy clean-up for the maple bacon glazed bacon.
Use the shredder attachment for food processor to shred the Brussels sprouts, as it is safer than a mandolin and faster than a chef’s knife.
Preheat the oven to 400°F. Brush the slices of bread with oil and season with salt and pepper. Place in a single layer on a baking sheet and toast in oven until crisp and lightly golden brown, about 8 minutes. Remove and let cool. (Can be made several hours in advance)
Line a sheet pan with parchment paper. Place the bacon in a single layer on the parchment, not touching, and bake in the oven for 10 minutes, until just beginning to brown. Remove and brush the tops with the maple syrup and a sprinkling of black pepper, return to the oven and continue baking until crisp, about 10 minutes longer. Remove to a plate lined with paper towels and let drain and cool slightly. When cool enough to handle, but the bacon into medium-sized pieces.
While the bacon is cooking, melt the butter in a large sauté pan over high heat. Add the shaved Brussels sprouts and cook, stirring occasionally, until wilted and lightly golden brown, stir in the thyme and season with salt and pepper.
Put the ricotta into a bowl, season with salt and pepper and lemon zest and mix until combined. Mix together the Brussels sprouts and bacon in a bowl. Place a dollop of the ricotta on each slice of toast and top with the Brussels sprouts/bacon mixture. Serve warm or at room temperature.