Place the fennel in a large saucepan. Thinly slice the zest into matchstick-size strips and scatter them over the fennel. Add the lemon juice, 1 teaspoon of the salt, the peppercorns, coriander (if using), wine, and broth. Bring to a boil. Reduce heat, cover, and simmer until the fennel is tender, 15 to 20 minutes. Remove from heat. (You can cook the fennel ahead of time for 10 to 15 minutes. Set aside at room temperature for up to 4 hours. Warm over medium heat for 5 minutes.)Using a slotted spoon, transfer the fennel and lemon zest to a platter. Sprinkle with the remaining salt and the reserved leaves. Serve warm or at room temperature.