Mince the green onion. Halve the cherry tomatoes. Cut the broccoli into small florets, place in a microwave-safe container with 1/2 tbsp water, cover loosely with plastic wrap, and microwave at 600W for 50 seconds. Drain the water.

Remove the roe from the mentaiko casing.

In a bowl, mix the ground pork, mentaiko, minced green onion, and all the seasonings (sake, soy sauce, grated ginger, sesame oil, black pepper, and potato starch) until the mixture becomes sticky. Divide into 8 portions.

Lay 3 dumpling wrappers slightly overlapping each other. Brush the overlapping edges with water to seal. Place a portion of the filling in the center, leaving about 1cm at the top. Fold the bottom edge over the filling, brush with water, and roll tightly to form a rose shape. Repeat to make 8 roses.

In a pan, add water to about 1cm depth and place a heatproof plate inside. Line the plate with parchment paper and arrange the dumpling roses on top. Cover with a lid, steam on high heat for 1 minute, then reduce to medium heat and steam for 9 minutes.