I threw this together tonight. If you're missing some stuff like saffron or smoked paprika, don't sweat it - it'll still taste good. You can also use whatever seafood you want, but make sure it's stuff that cooks quickly.
4 tomatoes, large dice
1tbsp tomato paste
1 bulb fennel, diced (reserve stalks and fronds)
2 medium leeks, diced and washed (reserve tops)
1 link chorizo, removed from casing
1c white wine
Small pinch of fennel
2tbsp coriander seed, whole - measure out whole, then crush
2tbsp smoked paprika
1 pinch chile flake (more if you like more spice)
1lb mussels, cleaned
1lb firm fish, cut into cubes
1lb head-on shrimp, peeled and deveined (reserve shells and heads)
Combine water, shrimp heads/shells, chopped fennel stalk and chopped and washed leek tops in a pot. Bring to a boil, then lower to a simmer.
Bring a pot up to medium heat. Add some oil, then add the chorizo. Cook til browned, stirring to break it up. Add leeks and fennel bulb, saute for a few minutes. Add flour, cook for a minute or two to cook the flour taste out. Add tomato paste, stir and cook for about a minute. Add tomatoes. Increase heat and deglaze with white wine. Add saffron, coriander seed and chile flake. Salt and pepper to taste. Lower heat to a low simmer, and stir occasionally.
Add mussels to a colander. Set the colander over the pot with the shrimp, and place a lid over the top of the colander. Let the mussels steam for about 5 minutes - the liquid from the mussels will drain down into the pot below with the shrimp. Set the mussels aside. Strain the shrimp liquid into another bowl, then add to the pot with the tomato mixture.
Bring pot to a boil. Add shrimp and fish - allow them to cook for about 2 minutes. Turn off the heat, and add the mussels. Adjust seasoning (salt and pepper). Spoon into bowls. Top with fennel fronds.