Jalan Haji Abu is one of the easiest places to start eating in Muar. Look for otak-otak, the spiced fish paste grilled in leaves, along with noodles, satay, desserts, and the usual spread of Malaysian coffee-shop comfort food.
The best approach is to snack rather than sit down for one formal meal. Muar's food reputation comes from small things done well, and this street lets you try several of them in one short walk.