Increase the oven temperature to 450 F. Leave the ribs uncovered while the oven heats (this helps evaporate surface moisture so the crust stays crisp).
Mix the mustard layer: in a small bowl stir together 2 tablespoons dijon mustard, maple syrup, and apple cider vinegar.
Mix the crust: in another bowl combine panko breadcrumb, parmesan cheese, parsley, thyme, lemon zest, and olive oil. The crumbs should look evenly moistened, like damp sand. If they still look dusty, add 1 more tablespoon olive oil.
Brush a thin, even coat of the mustard mixture over the top and sides of each rib. Do not drown them; too much mustard can make the crust slide.
Press the herb crust onto the mustard-coated ribs. Use your hands and really pack it on so it adheres. Any crumbs that fall onto the pan can be sprinkled back on top.