So two guys are walking down the street, and they pass a bar with a sign that reads, “Nude Female Mud Wrestling!” The first guy says, “Wow, what do you suppose that’s all about?” The second guy replies, “I hear the biggest problem is finding the nude female mud – after that, it’s pretty self-explanatory.”

Ba-dum-bum! That joke – a real groaner, admittedly – came to mind a few months ago, when I had an amazing bowl of turtle soup in New Orleans. Earthy and rich, with a finishing splash of dry sherry that infused the whole thing with a supple undercurrent of sophistication, it was so good that I wondered aloud whether it would be possible to duplicate it at home. “I don’t know,” said my friend Matt, “but for starters, I’m pretty sure you’re going to need some turtle.”

True enough, and that’s the tricky part. Although eating turtle was once quite common in New York (the seminal “Larousse Gastronomique” reports that “at the beginning of the 19th century in New York, a popular entertainment was barbecuing turtles imported from the West Indies”), your average contemporary fishmonger doesn’t have a tank full of live turtles, and even frozen turtle meat is hard to come by in the city.

Contrary to what you might think, this isn’t because turtle is so exotic. Quite the opposite, in fact: It’s because turtle used to be extremely popular – so popular that it was overharvested to the point of near-extinction and became prohibitively expensive (many species are now protected, and much of what’s sold for human consumption has been farmed). This is what led to the development of “mock turtle soup,” which is usually made from less expensive and more readily available meats – calf’s head, oxtail, or chicken – and can still be found in many cookbooks. But after that amazing soup I’d had in New Orleans, mock turtle wouldn’t do – I had to have the genuine article. And I figured real turtle had to be available somewhere in the city, because I’d seen several wholesalers carrying it when I took a walking tour of the Fulton Fish Market last year. So I got on the phone and began inquiring.

Citarella? Nope. Wild Edibles? Nope. Fish Tales, in Brooklyn? Nope (“and I wouldn’t know what to do with it even if I could get it,” added the proprietor). Someone suggested Hong Kong Supermarket in Chinatown, “but it really helps if you speak the language.” I don’t, so I brought along a photograph of a turtle to use as a visual aid, which led to an amusing point-and-gesture routine. But in the end: Nope. Acting on another tip, I went to the Gramercy Meat Market on Second Avenue, where I was subjected to a cruel tease: “Turtle meat? Yeah, we carry that – but I’m out of it. Maybe next week.”

I couldn’t wait that long. With turtle turning out to be even harder to find than nude female mud, I reluctantly resorted to the Internet, where I found frozen turtle meat available at ExoticMeats.com ($17 a pound, plus overnight shipping). A day later, I was the proud owner of a five-pound tub of snapping turtle, the most commonly farmed breed.

So what does turtle meat look like? The legs and tail are darkish red, like pork, while the torso is light and looks a lot like rabbit – not surprising, perhaps, since turtle meat’s nutritional profile is nearly identical to that of rabbit: low in calories and cholesterol, and with almost no fat at all. So it turns out that the tortoise and the hare, legendary polar opposites, have a lot in common.

As for the soup – which was once considered such a delicacy that Queen Victoria and Prince Albert began their Christmas meal with it in 1840 – there are countless recipes floating around out there, but most of them begin with a roux and end, oddly, with chopped hard-boiled eggs. The finishing touch of dry sherry is common but not universal, with port or Madeira sometimes used instead. Some versions include bacon or ham, but this is the rare instance where I prefer to go pork-free, so as not to overwhelm the flavor of the turtle.

As I began to cut up the meat into small pieces, I found that the light meat is very smooth to the touch, while the dark meat is a bit tougher and sinewy. And the smell? It’s not quite fishy, but there’s a definite aquatic aspect to it.

That same mildly aquatic quality is evident in the soup, my version of which borrows elements from many others (see accompanying recipe). The result is a bit thicker than what I had in New Orleans, but it’s still delicious. And the finishing spoonful of sherry – which you should add at the table just before everyone digs in, for a bit of ritualistic flair – is such a worthwhile addition that I may start trying it in other soups.

As for turtle meat, the folks at the Gramercy Meat Market (383B Second Ave., 212-481-1114) say they’re expecting their next shipment of it today. Grab it while you can – if my experience is any guide, the tortoise is a lot more elusive than the hare.

Turtle Soup

2 1/2 sticks unsalted butter
3/4 cup all-purpose flour
1 pound turtle meat, cut into 1/2 -inch cubes
1 cup minced celery 2 medium onions, minced
1 1/2 teaspoons minced garlic
3 bay leaves
1 teaspoon oregano
1 /2 teaspoon thyme
1/2 teaspoon freshly ground black pepper
1/2 teaspoon freshly ground nutmeg
1/2 teaspoon allspice
1 1/2 cups tomato puree
2 1/4 cups beef stock
2 1/4 cups fish stock
1/2 cup lemon juice
2 tablespoons Worcestershire sauce
5 hard-boiled eggs, finely chopped
2 tablespoons minced parsley
6 tablespoons dry sherry

1 Make a roux: In a large saucepan, melt 2 sticks of the butter. Add the flour and cook over medium heat, stirring constantly, until the roux turns light brown, about 12 minutes. Remove from heat and set aside.

2 In a Dutch oven or other large, heavy vessel, melt the remaining butter and add the turtle meat. Cook over high heat until the meat is brown, about 8 minutes. Add celery, onions, garlic, herbs, and spices. Cook until the vegetables are transparent, 2 to 3 minutes.

3 Add the tomato puree, lower heat, and simmer for 10 minutes. Add the beef and fish stock and simmer for 30 minutes more. Add the roux and stir to incorporate until the soup is smooth and thickened. Add salt and pepper to taste, and then add lemon juice, Worcestershire sauce, eggs, and parsley. Remove from heat and serve. At the table, add 1 tablespoon of dry sherry to each serving.

YIELD: Six servings