1. Center a rack in oven and heat to 425 degrees.
2. Toss asparagus and oil on a baking sheet until evenly coated, then season to taste with salt and pepper. Transfer to oven and roast until just tender, 10 to 15 minutes, shaking baking sheet once halfway through.
3. Meanwhile, melt butter, then transfer to a liquid measuring cup and let cool until very warm but not piping hot. Combine egg yolks, lemon juice, mustard, cayenne, and 1/2 teaspoon salt in a blender and puree for 10 seconds. With motor running, slowly add butter in a steady stream until a smooth and creamy sauce forms, about 1 minute. (If sauce is very thick, add 1 to 2 tablespoons warm water to reach desired consistency.)
4. To serve, transfer asparagus to a platter and drizzle half of hollandaise over top. Serve immediately with extra sauce on the side.
Source: Hannaford fresh Magazine, March - April 2020