Preparation

Heat the oil in a medium skillet over medium heat until it shimmers. Add the pancetta and cook, stirring occasionally, until the pancetta begins to render its fat, about 3 minutes. Add the shallot and cook, stirring frequently, until translucent and the pancetta is crisp, about 2 minutes more. Add the sherry vinegar and toss to combine. Remove from heat and set aside.

Line a large plate with paper towels. Fill a large straight-sided skillet with 3 inches of water and 1-1/2 tsp. salt. Bring to a boil over high heat. Reduce the heat to medium- high, add the asparagus, and cook, stirring occasionally, until the asparagus are bright green and crisp-tender, 2 to 4 minutes. Using tongs, transfer the asparagus to the prepared plate, leaving the water in the skillet. Pat the asparagus dry with paper towels, divide among 4 plates, and sprinkle with arugula, if using. Set the paper towel-lined plate aside.

Add the white wine vinegar to the water. Reduce the heat to maintain a medium simmer. Crack the eggs into separate small cups. Gently slide the eggs into the water. Using a spoon, gently swirl the egg whites back towards the yolks to form a more compact shape. Reduce the heat to maintain a low simmer and cook until the whites are set and the yolks are runny, 4 to 5 minutes. Using a slotted spoon, transfer the eggs to the paper towel-lined plate.

Place one egg on top of each plate of asparagus. Heat the pancetta mixture over medium heat until warmed through. Spoon the mixture over the top of the eggs and asparagus. Season with salt and pepper, and serve immediately.