How to Make It
Preheat the oven to 350°. Heat the olive oil in a roasting pan set over 2 burners. Add the fennel bulbs and cook over moderately low heat, stirring occasionally, until the fennel softens slightly and is just beginning to brown, about 20 minutes. Scatter the garlic, olives, cardamom and thyme over the fennel and season generously with salt and pepper. Pour the chicken stock into the roasting pan and bring to a boil over moderately high heat. Turn off the heat.
Place a crumpled sheet of parchment or wax paper directly over the fennel, then tightly cover the roasting pan with foil. Bake the fennel for about 1 hour, or until tender.
Remove the foil and the parchment paper and roast the fennel for 25 minutes longer, or until it is very tender and the liquid in the roasting pan has reduced to a few tablespoons. Transfer the fennel and olives to a serving platter. Remove and discard the cardamom pods and thyme sprigs. Serve the fennel warm or at room temperature.