Number of People
Slice each carrot and parsnip on the bias into 1-inch (2.5 cm) chunks. Slice the sweet potatoes into 1/2-inch (1 cm) thick rounds; cut each round in half. Place the vegetables in a large microwave-safe bowl. Cook the vegetables in the microwave, on high, for 6 minutes or until fork-tender but still firm.
Whisk the maple syrup with the melted butter, thyme, orange zest, salt and pepper. Toss the vegetables with the syrup mixture.
Turn the grill on. Select the Manual mode program, select red color setting and press OK. Once the purple indicator light has stopped flashing, place the vegetables on the grill and close the lid.
Cook, in batches, for 5 minutes or until the vegetables are tender and well marked; tent the cooked vegetables with foil between batches. Meanwhile, stir the vinegar into the syrup mixture left in the bowl. Once all the vegetables are cooked, return to the bowl and toss gently in the syrup-vinegar mixture to coat.