Heat a large pan over medium heat (I like to use a cast iron pan, but anything should work as long as you keep an eye on it). Gently lay the chilies in the pan and toast them for about 20-30 seconds (less if they begin to sear) per side. They should become softer, dark, and pliable.

Place the toasted chilies in a medium saucepan and cover with water. Bring the pot to a gentle simmer and cook for 10 minutes. Set the pot aside (do not discard the water).

Heat a large pan over medium heat (once again, I prefer cast iron for this). Add the pumpkin seeds and toast, stirring frequently. The seeds should begin to brown and pop after about 3-4 minutes, taking care not to burn them (if they do begin to burn, remove them from the pan and reduce the heat, then return them and continue). Add the sesame seeds and toast for an additional 2 minutes. Add the cloves and peanuts and toast for an additional minute. Make sure to stir everything regularly. Remove the mixture from heat and set aside.

Spread the tomatoes, onions, and garlic on a baking tray if using a broiler, or a grilling tray if using an outdoor grill (my preference). Char the ingredients under a high broiler or a medium grill; about 8-12 minutes, depending on the method you use. The shallot and garlic skins should be well blackened, and the tomatoes should be soft and splitting with a few charred patches. Set everything aside to cool.

Peel the cooled garlic and shallots and add them to a blender or food processor along with the tomatoes, chilies, and 1 cup of the cooking liquid from the chilies. Add all of the toasted ingredients, cinnamon, pepper, sugar, and vinegar. Blend until smooth.

Place the cleaned clams in a large pot. Add 3 cups of water, cover, and heat over medium. Allow the clams to simmer/steam until all the shells are open - about 5-7 minutes. Remove the clams, strain the liquid and set aside.

Heat the oil in a large pot until very hot; about 1 minute (you can use the clam pot again). Add the pureed pipian sauce, reduce the heat to medium, and bring to a gentle simmer. Add the broth and return to a simmer, and add the salt (make sure to taste the mixture, as the clam broth adds salt on its own). Cook for 5-10 minutes. At this point, you can either proceed with the next step to finish the soup, or reduce the mixture by about 1/3 (30-40 minutes) to make a thicker sauce-like soup.

Add the squid and shrimp and cook for 3-4 minutes. The squid should be firm, but tender. Add the clams and warm through, then serve, topped with a little avocado or cilantro.