Preheat the oven to 350°F.
Combine all of the honey mustard ingredients until smooth. Use a blender for a perfectly smooth sauce if you like. Season to taste.
Pat the tenderloin dry, place in a baking dish and coat with the honey mustard. Cover with aluminium foil and bake for 18-25 minutes, until the meat reaches an internal temperature of at least 145°F. Let the meat rest, covered, for 10 minutes before slicing and serving.
Place the butternut in a steamer basket inside a pot with 1 inch of water. Bring to a simmer, cover, and steam the squash until fork-tender, 15-20 minutes.
Meanwhile, heat the butter in a small saucepan over low heat until browned. Turn off the heat.
Transfer the cooked butternut to a blender with the browned butter, cinnamon, paprika, cloves and salt to taste. Purée until smooth.
On a baking sheet, toss the broccolini with the oil, salt and pepper. Roast until crisp and fork-tender, about 15 minutes.
Combine the lemon, parsley, garlic, oil and salt in a blender until mostly smooth to make the gremolata. Fold in the pumpkin seeds.
Divide the butternut purée, broccolini, and pork between plates. Garnish with pumpkin seed gremolata.