Step 1 Make the hollandaise sauce: Boil a few inches of water in a medium saucepan. Turn off the heat and place a metal bowl large enough to cover the saucepan on top, making sure the bottom of the bowl does not touch the water directly. Add the egg yolks and 2 tablespoons of water to the bowl and whisk continuously until the mixture becomes light and frothy. Continue whisking until the mixture thickens and forms a ribbon when you lift the whisk, about 5 minutes.
Step 2 Add the melted butter, a little at a time, to the egg mixture, whisking continuously, until you've incorporated all the butter. Add the lemon juice, a pinch each of salt and pepper, and the dill. Keep the hollandaise barely warm over the hot water. (Makes 1 1/2 cups sauce.)
Step 3Alternatively, you can make the hollandaise in a blender. Place the egg yolks, lemon juice, pinch of salt and white pepper in a blender. Add 2 tablespoons boiling water and blend for a few seconds. Melt the butter until it just starts to boil. Take the butter off the heat, turn the blender back on and add the hot butter in a slow, steady stream until combined. Pour into a bowl and stir in the dill.
Step 4In a large skillet over high heat, heat the olive oil until quite hot. Toss in the asparagus and a pinch of salt and cook, flipping the spears of asparagus so that they sear evenly. Continue cooking over high heat, until the spears roast and begin to caramelize but haven't lost their vibrant color or some of their crunch, about 5 minutes. Remove from the heat and place on a serving platter; serve with a bowl of the hollandaise sauce.