Rinse 2 cups of Calrose rice until the water runs clear, then cook according to rice cooker instructions, about 25 minutes. Let rest for 10 minutes.

In a microwave-safe bowl, whisk together 2 tablespoons of dark brown sugar, 1/4 cup of soy sauce, 1 tablespoon of mirin, and 1 teaspoon of sesame oil. Microwave for 30 seconds and stir until sugar dissolves.

Preheat a nonstick skillet over medium heat, spritz with cooking spray. Cook 8 slices of Spam for 4-5 minutes on each side until golden. Brush with teriyaki sauce.

Lay out a sheet of nori, shiny side down, and place the musubi mold at center. Ensure the mold is stable.

Scoop a generous amount of cooked rice into the mold, pressing down gently. Sprinkle 1 teaspoon of furikake on top, then layer 2 pieces of glazed Spam.

Carefully pull the nori over the Spam and rice, wetting edges to seal. Roll tightly with plastic wrap and let rest.

Slice the Spam Musubi in half diagonally using a warm, damp knife for presentation. Serve immediately.