In a skillet on medium heat, add cooking oil and sliced onions. Add a pinch of salt and a tablespoon of butter, mixing into the onions. Reduce heat to low and cook, stirring often, until the onions are soft and lightly golden. Add water to de-glaze the pan and cook until the onions are fully caramelized. Keep warm.

Add 3 eggs into an unheated skillet and scramble with a spatula until well blended. Add a tablespoon of butter and place the skillet on medium-low heat, stirring continuously to cook. Add a pinch of salt and chives, and cook until the eggs just start to set. Remove from heat and keep warm.

In a small bowl, combine the Sriracha and mayonnaise in a 1:2 ratio. Mix well.

Toast the brioche bun with butter and spread the sriracha mayo on both sides. Top with scrambled eggs. Melt the cheese slightly on a nonstick pan and place it on top of the eggs. Top with 1-2 tablespoons of caramelized onion and serve.