01 - Preheat oven to 425°F. Line a rimmed baking sheet with parchment paper for easy cleanup.
02 - Arrange trimmed asparagus spears in a single layer on the prepared baking sheet. Drizzle olive oil evenly over the spears, then sprinkle with sea salt and black pepper. Toss gently to coat all surfaces.
03 - Roast for 12–15 minutes until spears are tender-crisp and tips are lightly browned. Cooking time may vary based on spear thickness.
04 - While asparagus roasts, whisk egg yolks and fresh lemon juice in a heatproof bowl until the mixture thickens slightly and becomes pale yellow in color.
05 - Set the heatproof bowl over a pot of gently simmering water, ensuring the water does not touch the bowl bottom. Whisk constantly for 2–3 minutes until the mixture thickens enough to coat the back of a spoon.
06 - Slowly drizzle the warm melted butter into the yolk mixture while whisking continuously. The sauce will thicken and become glossy. Season with salt and cayenne pepper to taste.
07 - Transfer roasted asparagus to a serving platter. Spoon warm Hollandaise sauce generously over the spears. Serve immediately while the sauce is warm and asparagus is hot.