Chop and gently cook the scallions in oil until very soft and just lightly golden. Once cooled, transfer to an airtight jar and store.
Soak and clean the clams in a sink or a basin of cold water. Remove any open or floating clams.
Cut the tofu into 2cm thick cubes and set aside.
Bring a pot of water to a boil and immerse the clams until shells open, discarding those that do not open; then remove the clams and reserve 250ml of the clam broth.
Blanch the tofu quickly and place on a plate. Heat a wok and add scallion oil and soy oil, then add the pickled bell pepper, salt, sugar, and crushed garlic, stirring well until fragrant.
Add the clam broth and beer to the wok and cook for 5 minutes, as the spicy garlic flavor transforms into the aroma of scallions in the broth. Add the clams and simmer for half a minute over low heat.
Serve the stew in a large serving bowl, add the tofu, and sprinkle with chopped scallions for garnish.