Preheat the oven to 375°F.
Toss the potatoes on a baking sheet with the oil, salt, and pepper. Roast until the potatoes are fork-tender, but not mushy, about 20 minutes. Let cool, then toss the potatoes with thyme, parsley, and lemon juice.
Combine the lemon, parsley, garlic, oil and salt in a blender until mostly smooth.
Coat the salmon with the gremolata on a baking sheet and roast until cooked through, 10-15 minutes.
Toss the fennel with 1 tablespoon oil, salt and pepper on a baking sheet. Roast for 8 minutes, or until golden.
Meanwhile, heat a skillet over medium and cook the bacon until crisp, turning once. Transfer to a paper towel-lined plate and chop or crumble when cool.
In a large bowl, toss together all of the celery root remoulade ingredients. Season with salt and pepper.
To serve, divide the roasted potatoes, fennel, and salmon between plates. Top with celery root remoulade, crumbled bacon and parsley.