Rinse 2 cups of uncooked short-grain white rice under cold water until clear. Combine with 2 cups of water in a rice cooker or pot and cook.

Slice Spam into 8 pieces, each about 3/8-inch thick. Set aside.

In a bowl, whisk together 1/4 cup soy sauce, 2 tablespoons dark brown sugar, 1 tablespoon mirin, 1 teaspoon seasoned rice vinegar, and 1 teaspoon sesame oil until sugar dissolves.

Heat 2 tablespoons vegetable oil in a skillet. Add Spam slices and fry for 2-3 minutes until golden brown.

Pour glaze into the skillet and coat Spam, simmering for 1-2 minutes until it thickens.

Cut sushi nori into strips approximately 2 inches wide.

To assemble, fill a musubi mold with warm rice, press down, place a slice of glazed Spam on top, and add another layer of rice if desired.

Wrap with nori; moistening the edges to seal.

Serve warm or wrap individually for on-the-go snacking.