Meat... 0.25 pounds of ground beef, at least 15% fat... 22% is even better. You can season it if you want, but a little salt and pepper is probably all you need.
Grill it. Medium to medium well and place a slice of american cheese on it when you remove it form the grill. (IMHO, american cheese is vile stuff suited for hamburgers and grilled cheese sandwiches and nothing else.)
Lightly toast the bun (roll).
Now stack from the bottom up:
1. Bun
2. Mustard (standard yellow... no honey mustard or dijon)
3. Meat
4. Cheese (already placed)
5. 3 slices of sweet pickle (dill is okay too)
6. 1 slice of tomato
7. 1 slice raw red onion (or... grilled white onion)
8. leaf of iceberg lettuce
9. mayonnaise
10. bun.
Or... repeat 3 and 4 for a double.
Serve with french fried potatos, garnished with Heinz-57 Ketchup and a Coca-Cola with crushed ice (or a chocolate milk-shake). Do not dip fries in mayonaisse. It is an unholy abomination to do so.