Combine the Sriracha and mayonnaise in a small bowl. Whisk until the mixture is even in color. Set aside.
To caramelize the onion:
Set a sauté pan over medium-high heat. When the pan is hot add 1/2 tablespoon of the butter and let it melt. Add the onion and reduce the heat to low. Cook, stirring often, until the onion is very soft and golden brown, about 45 minutes. Set aside.
To cook the eggs:
Crack 3 eggs into a cold sauté pan and add the remaining 1 tablespoon of butter. With a wooden spoon, stir the egg and butter mixture well, blending the yolks and whites to a uniform color. Do not stir vigorously: Whipping the eggs will ruin the consistency of the cooked eggs.
Place the egg mixture over medium-high heat. Stir the eggs until the edges begin to curdle. Once the eggs start to coagulate, remove from the heat and stir the curds off the edges of the pan. Place the pan back on the heat and stir the eggs until they’re the consistency of a thick custard. Add the chives and season with salt to taste. (Seasoning has to occur at the very end or the salt will break down the proteins, resulting in watery eggs.) Transfer the scrambled eggs to a metal bowl.
Split and toast the bun and spread the Sriracha mayo on both halves. Pile the scrambled eggs onto the bottom half. Add the slice of cheddar to a hot nonstick sauté pan to melt it slightly, then arrange it on top of the eggs. Top with 1 tablespoon of the caramelized onions, cap with the bun top, and serve.
Rubio's is credited with bringing fish tacos to the states and their beer-battered fish taco is the recipe that started it all since 1983. Oh So Delicioso has shared their awesome copycat version and we are HERE FOR IT.