1 Frenched rack of lamb (8 ribs total), rack cut in half
1/2 teaspoon onion powder
1/4 teaspoon garlic powder
3/4 teaspoon salt, divided use
1/2 teaspoon black pepper, divided use
1 cup fine fresh bread crumbs
1 large clove garlic, minced
2 tablespoons finely chopped fresh flat-leaf parsley
2 teaspoons finely chopped fresh mint
1 teaspoon minced fresh rosemary
1 tablespoon melted butter
2 tablespoons olive oil, or more as needed, divided use
1 tablespoon Dijon mustard