Add oil to the griddle, then sauté the sliced onions and Serrano peppers until softened and lightly browned.
Spread mayonnaise on both sides of each bread slice and toast on the griddle until golden and crisp. Remove and set aside.
Crack the eggs directly onto the griddle, cooking sunny side up. Season with Blackstone All Purpose Seasoning, salt, and black pepper.
While the eggs cook, place the turkey ham slices on the griddle and sear until lightly browned on both sides.
Grill the tomato slices until slightly softened with light grill marks.
Just before the eggs are done, add a slice of American cheese on top of each egg to melt.
Assemble the sandwiches: spread more mayo on the toasted bread, layer on the cheesy egg, grilled tomato, onions, peppers, two slices of turkey ham, and lettuce. Close the sandwich and serve warm.
