Rinse asparagus under cool water, trim tough ends, and slice thinly on the bias.

In a skillet, heat olive oil and toast stale bread until golden and crispy, then pulse in a food processor.

In a bowl, combine asparagus, toasted walnuts, grated Parmesan, crispy breadcrumbs, lemon zest, salt, pepper, and red pepper flakes.

Squeeze lemon juice over the salad and mix gently to coat all ingredients.

Drizzle an additional tablespoon of olive oil before serving.