I sometimes miss Portillo's of the Chicagoland area. I was more a fan of the fries, shakes, and burgers--not so much the hot dogs or Italian beef. However, Lenny's fills that gap in my life. It is not to say this is a dupe of Portillo's; yes, it has similar decor and menu, but Lenny's carries its own weight.
The shakes come in the usual flavors; but my favorite is the horchata shake. I've had others, but Lenny's figured a way so it doesn't taste like a cinnamon vanilla candle.
Burgers are great and ample-sized; I really can't tell the difference between regular mayo and their ranch mayo though. Toppings are plenty, but they use shredded lettuce. The fries are nice and crispy; I think they use beer-battered ones, but don't quote me on that.
They charge an extra 30 cents to use a debit or credit card. It's better to carry cash when you go here.