10 cent package

The R.T. French Co. (French's) introduced instant potatoes in America in the early 1950's. From early ads, the boxes in the 50's & 60's contained either 8 or 10 servings. A serving is probably the same as later years, which would be 1/4 cup dry or 1/2 cup prepared.

Biscuit mix has been around since around 1930.

If the recipe has both instant mashed potatoes and biscuit mix, it would have to be from the 1950's or later. Because of the 10¢ reference, it was more than likely the 50's.

During this time frame, it was most likely the 8 or 10 serving box of mashed potatoes, 2 - 2.5 cups dry. Jiffy baking mixes in 8 oz boxes sold for 10¢ in the mid to late 1950's.

Without a good timeline to reference I don't know if we could directly answer your question. I will offer you an alternative, there is an excellent book Ratio: The Simple Codes Behind the Craft of Everyday Cooking which describes how many recipes can be analyzed as a ratio of A:B (for instance instant potatoes-to-biscuit mix). In this case you would need to figure out a good reference point, a third (or forth) ingredients (say, butter or water) which has a known value and reverse the math. From there you may need to experiment to find that balance that reminds you of 'how Mom used to make it' but this can get you on the right track.

A 10 cent box of Jiffy Mix was 8oz in 1957-58. I remember those well.

Historically, they may have come in more sizes, but back in the 60's and 70's there were a lot of recipes written this way that were written for Idahoan instant potatoes which came in envelopes. I recall there being some rivals at the time, but most were in the same size pack. Have seen them listed as 10 cent, 15 cent envelopes, maybe even 25 cent, but I really only recall one size being common and I think they are still available at about 2 oz.

If a book like Cos mentions does not have it, you may need to experiment, but with the full recipe it may be a lot easier to eyeball and say, yeah or nay that it seems about the correct size. It can be quite to mystery experience to break the codes of some of these old family recipes. I think my Mom's favorite was "one pink scoop, not the red one", because, of course, everyone had the same color coded measuring scoops she had. ;)