HEAT oven to 325ºF.
MIX dressing, syrup and mustard. Place ham, fat-side up, in roasting pan. Diagonally score ham; cover with foil. Bake 1 hour.
DISCARD foil. Brush ham with 1/3 of the glaze. Bake, uncovered, 1 hour or until heated through (140ºF), brushing with remaining glaze every 20 min. Meanwhile, toss parsnips and carrots with oil in large shallow pan. Add to oven with ham the last 45 min. of the ham baking time, turning vegetables every time ham is brushed with glaze.
REMOVE ham from oven; transfer to cutting board. Tent with foil; let stand 15 min. Meanwhile, increase oven temperature to 425ºF. Continue to roast vegetables 15 min., turning every 5 min. Serve with ham.