Cut the bamboo shoots in half horizontally, then slice them into 5mm thick pieces.

Pat the aburaage with a paper towel to remove excess oil, then cut it in half along the shorter side and slice into 1cm wide strips along the longer side.

Layer the aburaage, canned tuna, and bamboo shoots in a microwave-safe container. Add the seasonings (soy sauce and chicken broth powder), cover loosely with plastic wrap, and microwave at 600W for 2 minutes and 30 seconds.