What do you do to make soup cool?

You blow on it.

Or: you serve it in a cramped cellar on the Lower East Side with fewer tables than customers, do it until 1 AM, and ladle it out to a hip-hop beat.

Down on Farwell Avenue, a few blocks from the lake, and just across from Ardent — whose chef, Justin Carlisle, is one of the most renowned in the city — is a ramen place that just might make Milwaukee famous: Red Light Ramen.

Carlisle — his family has a farm in Sparta, Wisconsin — worked with a Japanese chef when he was coming up and was left craving ramen after a cook’s tour of Tokyo. He used to serve the soup inside Ardent (converted hastily for the occasion after the last customers had left) in the very late hours on Friday and Saturday night, between 11:30 and 1. His main clientele at the beginning consisted of cooks from other restaurants, sick of fried bar food or hot junk from a drive-thru but looking for something flavorsome and comforting.

But that was way back in 2015.

Now Red Light occupies its own space. It’s a hit, and the soup is the reason why. If the word “ramen” makes you think of the styrofoam cups full of bright yellow coils coming out of the dorm microwave, expunge those college memories now. Even to call this ramen “soup” is a sad understatement. It’s a banquet in a sturdy china bowl under a steaming sheet of stock.

We tried both of the only two forms of ramen available here: the pork-based classic Tonkotsu (豚骨) and a vegetarian option, miso (みそ or 味噌).

Tonkotsu is, we are told, native to southern Japan. It is perhaps the most traditional style of ramen. The broth is not clear like a French consommé but cloudy: milky with emulsified fat. At Red Light, so they say, it’s boiled for at least 15 hours, and the pork is assisted by kombu (kelp), dried mushrooms, ginger, garlic, scallions, odd chicken pieces and even beer.

The broth is the soul of good ramen.

And the noodles are the body: they have to be springy and toothsome, or it’s not real ramen.

Red Light’s passed the test.

Also into the bowl go pork slices, two sesame-sprinkled halves of a custard-centered hard-cooked egg, scallions, a dry sheet of nori (seaweed), mushrooms, and what we believe to have identified as spinach and bamboo shoots.

An amazing orange chili oil as well as soy sauce are on all the tables, ready to be sprinkled in. But really: this soup doesn’t need it.

The miso option (recommended on Friday for Catholics) has a clear broth that is the very essence of umami (うま味) — the brothy, meaty taste which is best described in English by a Japanese loan-word.

That this flavor is achieved without meat — miso being essentially fermented soy beans — is a tribute to Red Light’s art. This version also includes the egg, bamboo shoots, nori and scallions, but also the elegant spindly white mushrooms called enoki (榎). It’s a delight to the eye.

Armed with chopsticks, we slurped the noodles out first, as we believe one ought to do to prevent them from getting too soggy. Then we let the broth wash down in spoonfuls. Then we spindled the egg and meat and vegetables.

We were deeply content.

Other things we tried here included a charred octopus amuse-bouche, which made the 15-minute wait for the soup more bearable. The addition of shredded white radish ribbons and a bed of spot-on kimchi — the Korean-style fermented cabbage and vegetables — is what really made that dish. Octopus in se ipso is more about texture than taste.

There is also a weird custom in this house of serving “boozy slushies”. Despite the frigid temperatures outdoors, we tried a brandy old fashioned slushy that faithfully reproduced the patriotic Wisconsin standard in frozen form, including a deep red cherry on top. Recommended.

Now: those who dare be “in” and try Red Light need be wary of a few sticking points. You make your reservation here in person, by coming in and announcing yourself at the bar. But then, there’s no place for you to wait inside the restaurant. So you stand with the others outside on the sidewalk, like mad fans queuing for a Kiss concert.

That can be challenging in February in Milwaukee if the wait time is (as it was for us) about 35 minutes.

The restaurant kindly provides an umbrella-shaped standing gas heater like the kind seen on the terraces of Paris cafés for its sidewalk-stranded patrons. But that only goes so far. We waited in our car and kept the heat on full blast. If you want to avoid the wait, I hear it’s best to come after 10 on a Wednesday or Thursday night.

Also: the setting is indeed “intimate” — not to say cramped — and you all sit around on backless stools. Many customers ate in full winter regalia, perhaps removing a stocking cap but never daring to free themselves from their puffy parkas. Adding to the railway-canteen atmosphere is the occasional homeless visitor, who has to be unceremoniously bounced by one of the servers.

In a restaurant this small, you see it all.

But the wait and the grit — and the fact that you’re a flight down from a concrete sidewalk at demi-basement level — give the place a sort of louche appeal that ratifies its double-meaning name.

The crowd is hip: a few oldsters, a lot of youngsters, and quite a few folks who looked recently arrived from the Far East. Decade-old hip-hop thumps on the speakers (shoutout to Lil Wayne).

You know? It is nice to be right in the heart of Milwaukee and feel so Japanese you almost expect Farwell Street to quake and Lake Michigan to disgorge a small tsunami.

It’s nice to feel like an off-duty sous chef; to be the one who knows which narrow stairway leads down to good food. (At this place after 10, you expect a visit from a tipsy Gordon Ramsey.)

And it’s good to slurp your glistening noodles and inhale the smell of kelp and fat and know this city grooves in hidden places. We permute and mutate and cook to a globalized rhythm… all while clinging faithfully to a freezing cold brandy old-fashioned.