For the cauliflower: Preheat the oven to 450 degrees F. In a small bowl, whisk together the oil, mustard, paprika and some salt and pepper Brush the cauliflower sections with the spice oil. Place flat on a sheet tray and roast for 10 minutes. Carefully flip the cauliflower and return to oven and roast until golden, another 10 to 12 minutes.
For the mustard: Meanwhile, mix together in a small bowl the yellow mustard, honey and stone ground mustard. Season with salt and pepper. Set aside.
For the sandwich build: Add the butter to griddle over medium-low heat. In between two pieces of lavash, spread some honey mustard, layer shredded butterkase, a portion of cauliflower, pears and finally more shredded cheese. Place the sandwich on the griddle, covering with a metal bowl. Cook until golden and crisp on the outside and gooey in the middle, 4 to 5 minutes per side.
For the salad: Mix the watercress, dill and radishes together, and toss with the lemon juice and some olive oil. Season with salt and pepper and serve on the side of the cauliflower melt.