Parsnip-Cakes
"Scrape some parsnip-roots, and slice them thin, dry them in an Oven and beat them to Powder; mix them then with an equal quantity of Flour, and make them up with Cream and Spices powder'd; then mould them into Cakes, and bake them in a gentle Oven. N.B. The sweetnes of the Parsnip Powder answers the want of Sugar."
The Country Housewife and Lady´s Director, London 1728-32
These little cakes have the look and texture of soft oat cakes, rather sweet though, without enough spice, they can be fairly parsnipy tasting.
notes
This depends on how many parsnips you plan to use (you will want plenty). As noted below, this mixture can take on a lot of spice unless you really want to only taste parsnip... adjust to taste and choose what spices you enjoy together.
After you have made your parsnip flour, then weigh it and add the same amount of wheat flour.
What I would change: I would not be so shy with the spices... what I decided to add (as it is apparently up to cooks taste) was a little ground caraway, some coriander, a little mace, some cinnamon and some ginger. I found the sweetness of these cakes to hold up well to the spices and it could have certainly taken more than I offered... and cloves would have worked well... it certainly wanted cloves.
Parsnip Flour
On doing it again, I wouldn't thinly slice the parsnip as instructed but would rather have grated it. I sliced those buggers pretty darn thin but found it did not like to break under the pressure of a pestle and it would get stuck in the blades of a processor so, failing even that, I turned to a mill which took care of it nicely but not entirely easily. These were dried beforehand in a slow oven and then let to dry further for several days, you do really have to make sure the slices of parsnip are very thin and very dry beforehand.