Build your sandwich from the bottom up. Bread, cheese, ham, sauce, pineapple, cheese, bread.
Once pan is hot, place sandwich in and cook on each side until cheese is melted and bread is toasted (probably 3-4 minutes per side, but will depend on heat). There's no need to add butter or oil to pan because croissants are FULL of butter (which is why they are so delicious).
Remove and enjoy!
Amounts of cheese, ham, pineapple and sauce can be varied to taste. I used brie, but you can sub any cheese you prefer.