Prepare sliced ham, cheese, eggs, onion, and mayonnaise.
Scramble the eggs and cook them in a pan.
Lightly grill the ham in a pan.
Finely chop the onion and soak it in cold water to remove the sharp flavor.
On one slice of bread, layer ham, cheese, scrambled eggs, onion, and mayonnaise in order.
Cover with another slice of bread and cut it in half diagonally to make triangles.