Preheat the oven to 350°F (180°C) with the fan on. Blend the mustard, honey, olive oil, cumin, zest, plenty of pepper, and vegetable bouillon cubes in a food processor and set aside.

Score the meat in a diamond pattern to help it absorb the marinade, and rub the marinade all over the meat.

Place the meat in a baking dish covered with parchment paper and aluminum foil. (You can also use a roasting pan.) At this point, you can let the meat marinate in the refrigerator for up to 24 hours.

Roast in the oven for 3 hours. Shortly before the 3 hours are up, prepare the glaze. In a bowl, combine the honey and brown sugar, cover with plastic wrap, and microwave for 1 minute at 800 watts. Remove the plastic wrap from the glaze and stir to combine the ingredients.

Remove the pork from the oven, take off the parchment paper and aluminum foil, add the potatoes, carrots, and cinnamon if using, and pour the glaze over the meat.

Return to the oven at 400°F (200°C) with the fan on for about 30 minutes. Serve by drizzling with the juices left in the baking dish.