Cut the tofu into 1 to 1.5 cm thick slices, blot off any excess surface moisture with kitchen paper towels (no need to press out the water), and place on a sheet of aluminum foil.
Scrape out the tarako eggs from the membrane.
Mix together the tarako, mayonnaise and soy sauce to make tarako-mayonnaise, mound on top of the tofu from Step 1, and cook in a toaster oven for 5 to 6 minutes.
(Don't close up the foil!)
When it's become a little browned on top, it's done.
Place a plate, foil and all, and sprinkle on top with the chopped green onion.