- 4 spring onions or 6 scallions, whites only, thinly sliced
- 1/4 cup apple cider vinegar
- 2 teaspoons sugar
- 1 teaspoon kosher salt
- 12 slices thick-cut bacon
- 2 tablespoons pure maple syrup
- 1/4 cup mayonnaise
- 1 tablespoon Sriracha
- 8 slices white sandwich bread, such as Pullman
- 1/4 cup mayonnaise
- 2 tablespoons unsalted butter
- 4 large eggs
- Kosher salt, ground pepper
- 1 cup arugula leaves
- Combine onions, vinegar, sugar, salt, and 1 tablespoon water in a small bowl and toss to combine; let stand for 30 minutes.
- Preheat oven to 350°F. Place bacon on a foil-lined large rimmed baking sheet; brush both sides with syrup. Bake until bacon begins to crisp but is still pliable, 20-25 minutes.
- Mix mayonnaise and Sriracha in a small bowl to combine; set aside.
- Spread 1 side of bread slices with plain mayonnaise. Heat a large skillet over medium-low heat. Working in batches, cook bread, mayonnaise side down, until brown and crisp, about 3 minutes. Wipe out skillet.
- Melt butter in same skillet over medium heat; crack eggs into skillet. Cook, occasionally basting with butter in skillet, until whites are set, about 3 minutes. Season with salt and pepper.
- Spread untoasted side of each bread slice with spicy mayo. Build sandwiches with bread, bacon, eggs, pickled spring onions, and arugula.