First preheat the oven to 325F. Mix the dressing, syrup & mustard in a small bowl. Then place ham fat side up in a roasting pan. Then diagonally score the ham. Cover with foil & bake for about 1 hour.
Next Remove the foil & brush the ham with 1/3 of the glaze. bake again uncovered for about 1 hour more or until fully heated. Brush with remaining glaze about every 20 mins. In a large shallow pan toss the carrots & parsnips with the oil. Add them to the ham at the last 45 mins of baking. Make sure to turn the veggies everytime you brush the ham with glaze.
Then remove the ham from the oven & tranfer to a cutting board. Tent with foil & let stand for about 15 mins. In the mean time increase the heat to 425F. Continue to roasr theveggies for about 15 mins, turning every 5 mins & serve with the ham.