Meanwhile, prepare the butternut squash: Wash the outside of the squash well. Using a sharp knife, carefully cut the butternut squash in half and scoop out and discard the seeds. There is no need to peel the squash.
Place the half squash on the cutting board with the cut side down (so it doesn’t roll) and cut in half again, then slice into ½-inch slices.
TIP: To make them cook quicker on the grill, microwave or steam the squash pieces for a few minutes before tossing in the dressing.
Mix the oil, brown sugar, salt and pepper and lime juice in a large bowl. Add the squash pieces and toss to coat. Reserve any leftover dressing.
Place the squash onto the grate and grill (uncovered) for 10-15 minutes, or until tender, turning occassionally.
Place the cooked squash onto a serving plate, drizzle with any leftover dressing, and sprinkle with the lime zest, chili flakes and cilantro.