Preheat oven to 400°F. Set garlic butter spread out to soften.
Add oil and sliced Vidalia onions to a large skillet. Season with salt and pepper.
Cook the onions slow and low over medium-low to low heat, stirring occasionally, until soft and golden brown.
Turn off the heat. Reserve a small amount of Swiss cheese for topping.
Add mayonnaise and the remaining shredded Swiss cheese to the skillet. Stir with the caramelized onions for a couple of minutes until creamy and incorporated using the residual heat.
Keep the King’s Hawaiian rolls together in their original tray. Cut a small square from the top of each roll and remove the center, being careful not to cut through the bottom.
Save the removed bread pieces for serving with any extra dip.
Generously spoon the hot onion dip into each bread bowl.
Brush softened garlic butter over the tops and around the sides of the rolls.
Sprinkle the reserved Swiss cheese over the filled centers.
Bake at 400°F for about 10 minutes, until hot and melty.
Broil for about 1 minute, watching carefully, until the cheese and tops are golden brown and bubbly.
Serve immediately and watch everybody go CRAZY!