Rinse 2 cups of Calrose rice under cold water until the water runs clear. Cook according to package instructions for about 18-20 minutes. Let it rest for 5-10 minutes.

In a small saucepan, combine dark brown sugar, soy sauce, mirin, and sesame oil. Heat over medium heat, stirring until the sugar dissolves. Let cool.

Slice the Spam into 8 equal rectangles. Pan-fry in a heated skillet for 3-4 minutes on each side until crispy. Drizzle teriyaki sauce over Spam and cook for another 2 minutes.

Lay a nori sheet shiny side down on a clean surface. Place a musubi mold in the center.

Scoop a layer of cooked rice into the mold, pressing down gently. Sprinkle furikake on top, then add a slice of glazed Spam.

Fold the nori over the filling, pulling tightly to encase it. Seal the edge by dabbing water along the seam.

Using a warm knife, slice each Spam Musubi in half and serve immediately or store in an airtight container.