Step 1

For the Hash: Place potatoes in a 3-quart saucepan and cover with 2 quarts cold water. Add vinegar and 2 tablespoons kosher salt. Bring to a boil over high heat. Reduce to a simmer and cook until barely tender, about 7 minutes after coming to a boil. Drain potatoes in a colander, then set aside.

Step 2

Meanwhile, heat a large cast iron skillet over high heat for 5 minutes. Add asparagus and serrano to the pan and arrange in a single layer. Cook, turning occasionally until asparagus and serrano are charred all over and asparagus is just cooked through, 4 to 6 minutes for thin spears, 5 to 8 minutes for thick spears. Carefully add 1 teaspoon (5ml) pork fat (or vegetable oil) to the skillet, toss to coat vegetables, and season lightly with salt and pepper. Transfer vegetables to cutting board. Once vegetables are cool enough to handle, cut asparagus into 2-inch pieces and de-seed and finely mince the serrano. Set aside.

Step 3

Wipe out skillet, return it to stovetop, and lower heat to medium. Add 1 tablespoon plus 2 teaspoons (25ml) pork fat (or vegetable oil) and pulled roast pork shoulder to now-empty skillet, and arrange pork in a single layer. Season lightly with salt and pepper, and cook, stirring occasionally, until pork is golden brown and crisp on all sides, 8 to 10 minutes. Using a slotted spoon, transfer pork to a plate and set aside.

Step 4

Add remaining 2 tablespoons (30ml) pork fat (or vegetable oil) to skillet and increase heat to medium-high. Add potatoes and arrange in as even a single layer as possible. Season lightly with salt, and cook, stirring and tossing occasionally, until potatoes are deep brown and crisp on all sides, about 20 minutes. Add coriander, chili powder, and cumin and cook, stirring frequently, until fragrant, about 30 seconds. Return pork, asparagus, and serrano to the skillet, along with any drippings reserved from roast pork shoulder (if you have saved them), toss to combine, and continue to cook until all components are heated through, about 2 minutes. Season with salt and pepper.

Step 5

For Serving: Sprinkle scallions and/or cilantro over the hash, and top with fried eggs (if using). Serve right away, passing warmed tortillas (if using), lime, and salsa verde at the table.