Had 1st time NYC visitors from Colorado & California that didn't know what a Knish was. World Renowned, Yonnah Shimmel Knishes on E Houston St on the Lower East Side was a 107 yr old Historical Treat! I've been going there for 55yrs.
We had the traditional round Potato & Cherry Cheese Knishes, & Dr Brown Sodas. They are Baked (never fried) in the Basement & sent upstairs via the original Dumb Waiter. Lots of Old photos cover the walls.
Inexpensive: Knishes- $3.75@ & cans of Dr Brown $1.75. Take a few home-they freeze very well. They also have, Spinach, Broccoli, Kasha, Blueberry & Cheese Knishes.
Yonnah' is Very Very Casual.
Next stop, Katz's Deli for piled High Corned Beef & Pastrami sandwiches.

This lower east side institution is famous for its knishes -- which if you haven't had one is a kind of potato pastry and a Jewish delicacy. Walking in you can definitely see glimpses of the bakery's past (this place dates to 1910). Of course in 1910 they likely did not have a jalapeno knish, as they do today (and it was good -- plenty spicy -- potato, jalapeno and cheese mixture). We also tried the traditional potato, and potato and spinach. Both were nicely spiced, not the bland ones you often get in other places. We were lucky that on an Easter Sunday we walked right up to the counter, bypassing the lines that are evident other days. There is also a small area to sit, and a deli-inspired menu. Definitely a throwback, but well worth the visit.

Best (only) knish bakery I have ever visited. My spinach knish was excellent, creamy, nicely spiced. Many steps up from those nasty square knishes you find at some restaurants and street carts.

As a native New Yorker, I always wanted to try a knish from this famous place. Glad we did but will probably not return. The potato knish was good and the kasha knish had too much potato and not enough kasha. Our local deli does better. It is a shame that the Carnegie Deli closed because they had the best potato knish in town.
Anyway, if you are in the area, give it a go. There are many varieties. Don't expect much from the place as it is run down.

Been eating here for decades. Moved out of state 25 years ago and we always grab knights to take home on visits to The City. They figured out how to make a perfect potato knish generations ago, and the soft, smooth, creamy taste is always the same. I will say I've tried several of their other styles over the years, but meh. I've learned if I'm going out of my way to get to Yonah Schimmels (also Katz's pastrami on rye!) I should just get the best, the Potato.