Remove seeds and pulp from the pumpkin, cut into half-length pieces, and slice into 5mm thick slices. Mince the green onion.

Cut the pork belly into 10cm wide pieces.

Layer the pumpkin and pork belly alternately on a microwave-safe plate. Pour sake over the layers, cover loosely with plastic wrap, and microwave at 600W for 5–6 minutes until cooked. Let it sit for 2 minutes with the wrap on.

Mix the sauce ingredients (green onion, garlic, ponzu soy sauce, sesame oil) in a bowl.