Start by peeling the hard-boiled eggs and placing them in a mixing bowl. Use a fork to mash the eggs lightly; you want them broken up but not completely pureed.
Add the Dijon mustard, mayo, chopped green onion, Spike Seasoning, salt, and pepper to the mashed eggs. Stir until everything is well combined. This mixture will be the star of your quesadillas!
Take one tortilla and spread a thin layer of butter on one side. On the unbuttered side, spoon a generous portion of the egg mixture and sprinkle with cheese. Top with another tortilla, buttered side facing out.
In a skillet over medium heat, place the quesadilla and cook until the bottom is golden brown, about 3-4 minutes. Carefully flip the quesadilla using your spatula and cook the other side until golden and the cheese has melted.
Once cooked, remove the quesadilla from the skillet and let it cool for a minute. Slice it into wedges and serve warm. You can pair it with salsa or guacamole for extra flavor!