Step 1: 1. Put the tuna into a bowl.
Step 2: 2. Add about one or more tablespoons of ketchup depending on taste.
Step 4: 4. Butter two slices of bread (if you would like).
Step 5: 5. Place lettuce slices on one of the bread slices.
Step 6: 6. Spread the tuna mixture on top.
Step 7: 7. Close the sandwich by adding the other bread slice on top of everything.