Q. What is it supposed to be on the show?

A. A bar inside a cafe.

 
Q. Where is it supposed to be on the show?

A.  In New York City.

Q. When did we see it on the show?

A. We see this spot in Episode 4 of Season 1 of Resurrection.
 
Dexter arranges to meet Lowell (the serial killer known as “The Tattoo Collector”, played by Neil Patrick Harris), for Happy Hour.

Lowell is already at the bar when Dexter arrives, but he tells Dexter he's going to have to cut their conversation short because he is planning to kill a young woman (Jules) who is getting a tattoo at a place across the street, called the “Silver Serpentine” tattoo parlor.

 
Lowell works as an anesthesiologist, and he shows Dexter that he has brought along brought along portable tanks of gas to knock out his potential victim when she walks home from the tattoo parlor after dark.

Dexter realizes that he is going to have to put an end to Lowell sooner than he expected, in order to prevent him from killing the girl, but Dex didn't bring along his equipment.

So Dexter improvises by sneaking up behind Lowell (as Lowell is about to grab the girl), and uses Lowell's own knockout gas to subdue him.
 
“The Tattoo Collector” wakes up on Dexter's kill table, which Dexter has set up at the tattoo parlor. 

Q. What is it actually in real life?

A. A bar inside a restaurant.

Q. Where can I find it in real life?

A. This scene was shot inside Aurora Brooklyn, an Italian restaurant located at 70 Grand St, in the Williamsburg neighborhood. 

That's on the southwest corner of Grand Street  & Wythe Avenue, in Brooklyn.
 
That's about midway between two other Brooklyn locations: The bowling alley (to the north) where Dexter and Mia go bowling, and the Navy Yard (to the south), where the police discover the dismembered body of Harrison's victim, Ryan. 

Google describes Aurora as an Italian restaurant “with rustic Italian food in a Tuscan-countryside setting”.

But in this scene, you don't see much of the place beyond the bar, which is located just inside the front door. 
 
In the following scene, where Lowell's potential victim, Jules, is walking down the street, and Lowell attempts to grab her from behind, she is walking west down the north side of Grand Street, basically right in front of the tattoo parlor. 

You'll find the restaurant's website at:  https://www.aurorabk.com
 

Here is a StreetView of the restaurant: 
 
 

Here is an aerial photo of the location.  And here is a map link.