¼ cup plus 2 tablespoons (3 ounces) unsalted butter

3 tablespoons capers, drained and rinsed

1 teaspoon fresh lemon juice (from 1 lemon)

Pinch of ground white pepper

1 to 4 tablespoons boiling water, as needed

8 smoked salmon slices (about 6 ounces total)

4 English muffins, split and toasted

2 cups packed arugula (about 2 ounces), roughly chopped

Place butter and capers in a small saucepan; heat over medium-low. Cook butter and capers, stirring occasionally, until butter browns and capers are crispy, about 6 minutes. Transfer capers to a small bowl using a slotted spoon; remove saucepan from heat. Reserve butter in pan. Whisk together egg yolks and lemon juice in a medium-size nonreactive metal bowl or glass bowl until well combined.

Add water to a medium saucepan to a depth of 1 inch, and bring to a low simmer over medium-low. Place egg yolk mixture in bowl over pan of simmering water, and whisk continuously (be sure bottom of bowl is not touching water). Slowly drizzle reserved warm butter into mixture, whisking vigorously until thick and creamy, about 6 minutes. Remove from heat, and whisk in salt, cayenne pepper, and white pepper. (If mixture is too thick, slowly add boiling water as needed, 1 tablespoon at a time, until desired consistency.)

Add water to a deep 12-inch skillet to a depth of 2 inches. Add vinegar, and bring to a low simmer over medium-low. Working in 2 batches of 4 eggs each, crack egg into a small heatproof bowl, being careful not to break yolk. Gently lower bowl into water, and carefully pour out egg; quickly repeat with remaining 3 eggs. Cook until egg whites are set, 3 to 4 minutes per batch. Transfer eggs to a paper towel-lined plate using a slotted spoon.

Place 1 salmon slice on each toasted muffin half, and top each with 1 egg. Spoon 1 tablespoon warm egg yolk mixture evenly over each egg, and top evenly with crispy capers. Top evenly with arugula, and garnish with chives. Serve immediately.

Capers can be crisped the day beforehand and kept in an airtight container in the refrigerator overnight. Butter can also be stored in the fridge and re-melted day of. Hollandaise sauce can be kept warm on the stove for 30 minutes.