1. Preheat oven to 450°F. Quarter squash lengthwise, then cut crosswise into 1-inch pieces.
2. Combine squash with sliced fennel, oil, thyme, salt and pepper in a large bowl. Spread mixture evenly on large, rimmed baking sheet. Roast for 10 minutes.
3. Stir in garlic and roast until vegetables are tender and fennel is beginning to brown, about 5 minutes more. Stir in fennel fronds and serve.
Alternativelyon grill, quarter squash and half fennel. Grill until slightly charred and soft. Cut into bite sized pieces while warm and mix with thyme, garlic, salt & pepper.