Cut about 10cm up the stems, removing the leafy stems. Reserve the leaves to use in salads, sauces or in other dishes such as roast chicken or pork.
Cut the bulbs into 6 or 8 wedges, depending on their size.
Trim away about 5mm at the root section.
Rinse the bulb very well ensuring that no sand remains.
Peel the onions and slice them vertically into 4 or 6 wedges.
Arrange the fennel and onion wedges in a flat baking dish.
Pour the stock over, cover with cling wrap and microwave on full power for 5 minutes. This will steam the vegetables, shortening the baking time. Pour off the liquid and reserve it to add to a gravy or sauce.
Mix the two cheeses, salt and pepper. Sprinkle half the cheese over the veggies and stir lightly.
Pour the cream over the vegetables.
Mix the crumbs with the remaining cheese and sprinkle this over the top.
Bake at 180°C for 20-30 minutes or until the topping is golden.