Generally, broccoli won't brown and crisp because there is too much water on the crown. Give your broccoli a good rinse when you bring it home from the grocer. Then towel dry prior to using in the dish. Be sure the crown is dry to the touch prior to step 1. Another reason the broccoli may not be browning is the pan is too full. Be sure to not overcrowd the baking sheet as that will cause the broccoli to steam versus brown. There should be plenty of space between the florets to allow the heat to circulate and brown. If you notice your pan is too crowded, pull out another and oven bake it on two!