Brush the zucchini with olive oil and put it on the grill, cut side down. Being careful not to overcook, grill the zucchini until soft but not mushy by moving it to the cool side of the grill.
Remove from the grill and let cool. Carefully scoop out the insides and put it on a cutting board, leaving the skin and a sturdy rim all the way around. Chop and reserve zucchini flesh.
Saute the onion in 1 tablespoon of oil, in a saucepan, over medium-high heat until it starts to brown.
Add the white part of the scallions, the raisins and pine nuts and saute for a minute more.
Add the rice and stir until coated, then add the stock, cinnamon stick, cardamom pods, star anise, bay leaf and hot pepper. Stir until well mixed, then lower heat and cover. Cook until tender, about 8 minutes. Discard the cinnamon stick, bay leaf, cardamom, anise and hot pepper. Stir in the reserved chopped zucchini, chopped dark green scallion tops, and lemon zest. Spoon the mixture into the zucchini shells, top with grated cheese and serve.
