Betty Kong, owner of Kay Lee Roast Meat Joint, left, prepares food as customers wait in line at the restaurant in Singapore, on April 18, 2012.

Think "most valuable recipes," and what comes to mind might be the secret formula for Coca Cola, say; or Col. Sanders' famous recipe for finger-lick'in good chicken. But now to that hallowed list must now be added a newcomer from Singapore: Betty Kong's recipe for roast-pork. She'll sell it to you for $1.8 million.

If you haven't heard of Kong, she and her husband run a little restaurant, the 60-stool Kay Lee Roast Meat Joint. So popular is its pork that patrons, according to Bloomberg, line up to be sure of getting in-sometimes an hour in advance.

The Kongs, however, are in their 60s are looking to retire. Neither of their kids wants to take the business over. So, they have put the Meat Joint up for sale, at an asking price of $2.8 million. Its assessed value is $1 million. The difference is the recipe.

Lee Ai Ming, a Singapore real estate expert quoted by Bloomberg, says the asking price represents a 20-fold increase over what a buyer would have to pay for any comparable joint. Ming calls the recipe "a very compelling example of the value of intellectual property."

Meat Joint loyalists call the recipe invaluable, variously praising its meat as "extremely yummy," "crunchy on the outside and tender on the inside," and "well marinated, very tasty, juicy." Says another, "It blows my mind."

So far the Kongs have received three offers-all below their asking price. Betty, 66, told Bloomberg her knees are giving out, but adamantly refuses to take a penny less than $2.8 million.  After the sale, she and her husband may travel the world, eating such unfamiliar delicacies as fish-and-chips in London or, in America, Kentucky Fried Chicken.

According to KFC, Colonel Sanders' original recipe is a mix of 11 herbs and spices. He wrote it in pencil on a single sheet of paper in 1940. In 2009, the company moved it from safe keeping to safer keeping, putting the old, yellowing sheet into a new, specially-designed electronic safe guarded by motion detectors and cameras. KFC describes the safe as weighing more than 770 pounds and having a half-inch thick steel door. AP reported the recipe was moved to it in a lockbox handcuffed to the wrist of a security consultant.

No word on where the Kongs store their secret recipe.

If this story whetted your appetite, try these pork recipes from "Good Morning America." No charge.

Michael Symon's Pork Tenderloin With Greens and Apples

Stephanie O'Dea's Slow Cooker Cranberry Pork Roast

Pork Loin With Apples and Prunes

Slow-Roasted Pork, Hirino Psito