Preheat oven to 400 degrees. Toss asparagus, olive oil, and salt and pepper together in a baking dish. Roast for 15-20 minutes or until crisp tender.
Meanwhile, pulse the bread slices in a food processor until you've made breadcrumbs.
Melt butter in a medium saucepan over medium-high heat. Add the crumbs and stir until they are golden and crisp. Spread on a plate to cool.
Pulse, lemon zest, herbs, garlic, salt and pepper in food processor until they are the same consistency as the bread crumbs. Mix together with cooled crumbs.
Plate asparagus and top with gremolata.