Onigiri Sandwich

1. Make Rice Balls: Preheat oven to 400°F. Combine dashi powder, soy sauce, mirin, and sesame oil in a small bowl. Place rice in a large mixing bowl and pour seasonings on top. Stir to combine.

2. Fill Molds: Place 12 (4") Mickey Mouse molds on a baking sheet lined with parchment paper. Fill each mold 1/3 of the way up with rice, and bake, 5 minutes. Set aside.

3. Slice Meat: Thinly slice beef short rib meat, removing large pieces of fat; set aside.

4. Cook Sauce: Combine soy sauce, mirin, sake, sugar, ginger, and garlic in a small saucepan. Cook over medium heat for 3 minutes, until simmering.

5. Thicken Sauce: Stir cornstarch and water in a small bowl and add to simmering liquid. Cook over medium-low heat for 1 minute, until thickened. Remove from heat.

6. Sear Meat: In a medium skillet over medium heat, heat sesame oil until hot, 3 minutes. Sear short rib slices until browned, 1 minute per side, then add sauce. Cook until bubbly, 2 minutes.

7. Make Sautéed Greens: In a medium skillet over medium heat, heat sesame oil until hot, 3 minutes. Cook greens until warm but still crisp, 3 minutes. Season with salt, pepper, and sesame seeds.

8. Assemble Sandwiches: Carefully remove rice balls from Mickey Mouse molds. Place 6 rice balls on a platter. Evenly divide beef and greens among rice balls. Top with remaining rice balls.