2Heat olive oil in a large saucepan; add onions, leeks, chopped tomatoes, and garlic. Cook and stir over low heat until vegetables have softened, about 3 to 5 minutes.
3Stir in fennel, thyme, bay leaf, and orange zest. Add mussels, shrimp, and boiling water; stir to combine. Season to taste with salt and black pepper. Increase the heat to high, and boil for about 3 minutes to allow the oil and water to combine.
