Adjust oven rack to middle position & heat oven to 450 degrees F. Line rimmed baking sheet with foil & spray with vegetable oil spray. Using fork, poke holes up & down stalks of asparagus. Toss asparagus with 1/2 tsp salt & let stand for 30 minutes on a paper towel line baking sheet.
Meanwhile, combine 1 C parmesan, panko, butter, 1/4 tsp salt, 1/8 tsp pepper & cayenne in bowl. Transfer 1/2 of panko mixture to shallow dish & reserve remaining mixture. Using stand mixer fitted with whisk, whip egg whites & honey until foamy, about 1 minute. Increase speed to medium high & whip until soft peaks form, 2 - 3 minutes. Scrape into 13 x 9" baking dish & toss asparagus in mixture. Working 1 spear at a time, dredge 1/2 of asparagus in panko mixture & transfer to baking sheet. Refill shallow dish with reserved panko mixture & repeat with remaining 1/2 of asparagus.
Bake asparagus until just beginning to brown, 6 - 8 minutes. Sprinkle with remaining 1/2 C parmesan & continue to bake until cheese is melted & panko are golden brown, 6 - 8 minutes. Transfer to platter. Serve.