Place chopped parsley, orange zest, olives, garlic, salt and red pepper flakes (if using) in a food processor and pulse a few times to combine. Scrape down the sides of the food processor and add olive oil. Process until a uniformly chunky texture is achieved.

Allow gremolata to sit at room temperature while you prepare the cioppino, to allow the flavors to fully bloom.

Prepare a stockpot with a steamer basket insert large enough to hold the clams and mussels. Bring 2 cups of water to boil in the stockpot, reduce heat to a simmer and steam mussels and clams under a lid until they just open, 5-8 minutes. Remove pot from heat and place all opened mussels and clams in a large bowl. Discard any mussels or clams that don’t open. Reserve the steaming liquid, about 2 cups.

In a large dutch oven or 8-quart stockpot, heat olive oil over medium until the surface just begins to shimmer. Add chopped onion, fennel and a hearty pinch of salt and saute until onion is softened and translucent, about 8-10 minutes. Add minced garlic, roasted red peppers, dried oregano and dried thyme. Saute until garlic is very fragrant and most of the liquid from the vegetables has evaporated.

When the red pepper mixture begins to look dry and sticky, add white wine. Use a wooden spoon to scrape up any vegetable bits clinging to the bottom of the pot. Bring mixture to a boil and simmer for 5 minutes.

Crush whole tomatoes roughly in your hands and add them to the white wine mixture along with any collected juices in the can, seafood stock and reserved steaming liquid. Allow mixture to simmer for 20 minutes uncovered. Taste and add salt as needed.

Add whitefish and shrimp to the pot and bring to a simmer. Cover the pot and cook for 2-3 minutes, or until the fish is opaque and shrimp are curled and pink.

Remove pot from heat and stir in mussels and clams. Taste and add salt as needed. Serve immediately, topped with a big spoonful of the parsley-olive gremolata.