Fennel is a delicious vegetable that is popular in Greek and Italian cuisine. If you’re not familiar with it, try this recipe as an accompaniment to roast meat or poultry. Serves 4 2 fennel bulbs. Discard the stalks and leaves 3 teaspoons balsamic vinegar 2.5 tablespoons olive oil Preheat the oven to 400º F. Slice the fennel bulbs into approximately one inch slices. Arrange them on a greased or lined oven tray. Drizzle the vinegar and oil over the sliced fennel. Roast for approximately 30 minutes, or until cooked and lightly golden.