Roasting asparagus at a high temperature concentrates its flavor and guarantees a tender—but not mushy—texture. To ensure crunchy crumbs, sprinkle them on just before serving.
Preheat oven to 425 degrees. Arrange asparagus on a rimmed baking sheet, and drizzle with oil. Season with 1/2 teaspoon salt and 1/4 teaspoon pepper. Roast until tender, 18 to 20 minutes, then transfer to a platter.
Meanwhile, melt butter in a medium skillet over medium heat. Add panko, and cook, stirring frequently, until deep golden brown, 8 to 10 minutes. Remove from heat, and stir in lemon juice and zest. Season with salt.
Top asparagus with breadcrumbs, and garnish with lemon.