Wash and clean the clams thoroughly with fresh cold water before you clean them again in salt water.
Slice the scallions into small pieces and julienne the ginger. Set aside.
Use a medium bowl and fill it with cold water, then add 1 tbsp of salt. Let the clams stand in this salted water for 1 hour. Afterward, drain them and rinse well.
Take a large, deep skillet and combine the measured sake and water and bring them to a boil.
Add the clams and cover the skillet tightly.
Start cooking them until most of the clams have opened. This takes about 4 minutes; make sure to shake the pan every now and then.
Remove any clams that did not open during the cooking process (these are spoiled).
Add the scallions and ginger and cook for one more minute.
Serve the clams and broth into medium-sized bowls and top them with butter, then garnish with the togarashi spice. Serve immediately for the best taste!