This is a guarache, and it is delicious. It is the signature food of the new Guarachez de Don Shuy at 4547 S. Sixth Ave. Big burritos, several kinds of fried tacos, tortas and other things are also available.
You may notice it comes with a fork and knife. This is because the soft corn tortilla thingamagig underneath cannot support the sheer weight of that enormous mound of veggies and meat on top. This is a good thing, especially considering it’s only $4.50 for one, or $7.50 for two.
There’s a little more information here.