Preheat oven to 400º F.

Toss the squash, fennel, onion, sprig of rosemary, and half the olive oil together. Season with a pinch or two of salt and pepper, and place on a baking sheet so the mixture can be spread out in a single layer. This will allow it to brown properly when roasting.

Roast, uncovered for about 30-40 minutes. Halfway through roasting, turn everything over and stir with a wide spatula, so it browns evenly on all sides.

While the squash mixture is roasting, make the dressing by mixing the chopped rosemary, mustard, honey, and remaining olive oil. Set aside.

When the squash mixture is done, remove it from the oven and let cool slightly. Toss the warm mixture with the dressing in a medium mixing bowl.

Taste for salt and pepper, then transfer to a serving bowl or platter and garnish with the optional pomegranate seeds and rosemary.