Halve fennel lengthways and cut each half into 6 wedges, keeping core intact. Blanch in a large saucepan of boiling salted water until tender (12-15 minutes). Drain and cool.
Preheat oven to 200C. Lay fennel pieces in a single layer on a baking paper-lined oven tray. Combine olive oil and garlic, pour over fennel, and scatter evenly with parmesan and reserved fennel fronds. Bake until golden and tender (20-25 minutes) and serve immediately.