Is there a consensus in your family on a favourite old family recipe that hasn't been served since you were kids? A salad popular in a past decade, an ethnic dessert lost with the immigrant generation? If you're very lucky, you already know how to make it, or a relative can show you. A beloved recipe lost with Great-Granny on the other hand, will probably be a big hit when it makes a sudden reappearance on the table, but will also take more legwork.
Finding the Recipe
Without someone to physically show you how to make a recipe, the next best thing is to locate the exact recipe used. Did anyone keep Gran's go-to cookbook, or has someone compiled a family cookbook? These are treasures, and if you don't already have one, compiling a family heirloom cookbook may be a good project for the future. (As you will see, however, "kitchen sense" can make these a challenge to compile, especially from the original sources!)
Online Searches
The Internet is a wonderful resource for locating a recipe that can't be located in your own family or that wasn't written down. If you know the exact name of the dish, you can simply Google it, but that's not always possible. The same dish could have different names, or it could be a foreign word which you only know how to say, not spell.
Before searching online, have some information to build on: try to determine as many of the ingredients used in the dish as possible, how it was prepared, how it was served and what it tasted like. Extra information like what area your family grew up in, (it might have been popular in your general region), the ethnic background of the person who prepared it and what times of the year it was usually served at can also be valuable clues.
Typing the recipe name into Google Images is a quick and easy way to match what you remember seeing on the table to what you think the dish may be called. Websites such as http://www.heritagerecipes.com, http://www.old-recipe-detective.blogspot.com and http://www.jellypress.com have a number of solved recipe mysteries and also accept new queries. (The two creators of jellypress.com have also written memoirs on genealogy and food: Laura Schenone's The Lost Ravioli Recipes of Hoboken details her search for a lost family recipe while Nancy Gail Ring's Walking on Walnuts researches both the lives and recipes of her family tree.)
The foodies at Chowhound (http://www.chowhound.chow.com) are very knowledgeable, helpful and fairly quick to respond to recipe queries as well. You will need to sign up as a member to post your question on Chowhound, but membership is free and you can post to different regional boards all over North America and the world.
Back of the Box Recipes
Not every family favourite has its origins in the rustic kitchens of the Old Country, however. Plenty of family favourites from the 20th century came from major food manufacturers such as Pillsbury or Bisquick; like now, companies would provide recipes on the back of boxes, the insides of labels and the backs of tins.
If you can remember any of the brand names particularly trusted by your family, it might be a clue. Many of these food companies now have searchable online recipe archives, and some even published their own cookbooks. A search of the recipe inventory at the website http://www.backofthebox.com may also help, although the forum doesn't seem to be used very often.
You Can't Go Home Again and "Kitchen Sense"
Especially if you've found it online, it's unlikely that mouthful of Christmas pudding or Swiss Steak will taste exactly the way Granny made it, most likely because she used "kitchen sense." The family behind the website Ohio Amish Country give this caveat about one of their Amish cookbooks: "Cooking is second nature to Amish women, so sometimes they don't think about giving step-by-step detailed instructions telling how and what to do."
This is by no means limited to the Amish. My aunt was frustrated many times trying to preserve my Eastern European maternal grandmother's recipes for posterity. There were no measurements, no set cooking or baking times and Grandma became rather annoyed at having to create her usual dishes in slow-motion just so that my aunt could see (and write down) what she was doing. I once attempted to do the same thing to my South American paternal grandmother, who waved away my pen and paper and said, "You're supposed to make it something like this, but it will be your own."
For that matter, take with a grain of salt any recipe which claims to be "authentic" or "Grandma's Style." This just means the recipe is the way the contributor's grandma made it; many traditional dishes, like meatloaf or Christmas pudding, are known by all but prepared uniquely by each family.
So once you're fairly confident in the recipe you have, go ahead and use your own kitchen sense to make it your own. No, it might not taste just the way Grandma used to make it, but it is your own, much like your own family history. Constantly changing, but with a clear link to the past, and hopefully, a big hit with the family gathered around this year's table.