Preheat your oven to 350°F. While the King’s Hawaiian rolls are still all connected, use a bread knife to cut the whole thing in half so there’s a top and bottom layer. Place the bottom layer on a non-stick or lightly buttered pan.
In a small bowl, combine the brown sugar and cinnamon. Spread a quarter cup of the softened butter across the bottom layer of rolls, then sprinkle 2/3 to 3/4 of the sugar/cinnamon mixture evenly over the buttered rolls.
Place the top layer of rolls back on and butter the top using the other half of the softened butter. Add the rest of the sugar/cinnamon mixture evenly across the top.
Bake for 15 minutes.
While you wait, make the icing: in a medium bowl combine the melted butter, powdered sugar, salt, milk, and vanilla. Start with 2 tbsp milk and adjust to your preferred consistency (add another tbsp if you want it thinner).
Once the rolls are done, transfer to a plate, drizzle on the icing, and enjoy. Ready in about 25 minutes.
