Strip the tough stalks and tough outer leaves from the broccoli so that you are left with the spears and tender leaves. Blanch in boiling salted water. When the water comes back to the boil, remove the broccoli and drain.
To make the crostini, toast the ciabatta slices on both sides and rub with the garlic.
Bring the stock to the boil, season generously, and add the blanched bro