Mix the corn base. In a medium bowl, combine the corn (2 cans), red bell pepper (1/2 cup), mayonnaise (1/2 cup), sugar (1 tablespoon), salt (1/2 teaspoon), and black pepper (1/4 teaspoon). Stir until evenly coated and creamy.
Add cheese to the mixture. Fold ½ cup of the shredded mozzarella directly into the corn mixture.
Heat the skillet. Place a 10-inch cast iron or oven-safe skillet over medium-high heat. Add the butter (2 tablespoons) and let it melt completely.
Warm the corn mixture. Add the corn mixture to the skillet and sauté for 2–3 minutes, just until heated through. Smooth out the mixture into an even, single layer.
Top with cheese. Sprinkle the remaining 1 ½ cups mozzarella evenly over the top.
Broil. Turn the oven broiler to high. Place the skillet on the top rack, close to the broiler, and cook for 3–4 minutes, until the cheese is melted, bubbly, and lightly golden. Watch closely to avoid burning.
Finish and serve. Remove from the oven, sprinkle with green onions, and serve immediately while hot and gooey.
Notes
Mix some cheese into the corn before broiling — this keeps the texture creamy instead of tight.
Watch closely under the broiler; cheese can go from golden to burnt quickly.
If the mixture seems thick before broiling, spread it gently — don’t press it flat.
Serve straight from the skillet for the best gooey texture.