Cook the bacon: Heat a medium skillet over medium-high heat and sauté the bacon until it becomes crispy, about 12 minutes, turning to cook it evenly. Drain on paper towels, reserving the fat in the pan.
While the bacon is cooking, prepare the Brussels sprouts: Remove and discard any damaged leaves. Then peel away the outer layer from each Brussels sprouts to yield a total of 3 cups leaves. Set those leaves aside. Thinly slice the remaining core pieces of the Brussels sprouts, and set them aside separately.
Make the Vinaigrette: In a large bowl whisk together 2 tablespoons of the reserved bacon fat with the olive oil, soy sauce, harissa and lemon juice. Stir in the shallots.
Cook the Brussels Sprout Leaves: Line a surface or plate with paper towels. Pour off any remaining bacon fat from the skillet and in the same skillet heat the vegetable or canola oil over medium-high heat until shimmering. Add the leaves, carefully – the may splutter when they heat the oil, and cook for about 3 or 4 minutes until crispy, stirring often. Transfer them with a slotted spoon to the paper towels, and lightly season them immediately with salt.
Assemble the salad: Add the thinly sliced raw Brussels sprouts into the bowl with the vinaigrette and toss with the mint and the parsley. Add the bacon and the warm crispy Brussels sprouts leaves, toss again and serve immediately.