Parsnips. if you are not familiar with them,  are a root vegetable that look like white carrots. the root starts out fairly fat but tapers quickly to a thin tail. This makes it sometimes difficult to cut them into pieces that will cook evenly, think thickness and mass. They have a sweetish flavor with a slight resinous tang.

This is the one of the simplest among over half a dozen recipes for parsnips recorded in de re coquinaria.  In other recipes they are used interchangeably with carrots and several recipes are direct parallels to ones calling for carrots.

• Parsnips, pared, or well scrubbed. and sliced or cut into chunks.

• good olive oil,

• fresh cilantro, chopped

• Pepper

Boil the parsnips in well-salted water until just tender. Drain and toss with chopped cilantro and a drizzle of good olive oil. sprinkle with whole or coarsely ground peppercorns

Another Way

Boil the parsnips in salt water {and season them} with pure oil, chopped green coriander and whole pepper.

  From Apicius  Cookery and Dining in Imperial Rome, Edited and Translated by Joseph Dommers Vehling, published 1936 by Walter M Hill, Chicago, reprinted 1977 by Dover Publications, Inc, NY  This translation has been criticized on a number of, valid, points. Several other translations into English have been published more recently. However, as a Dover reprint, the Velling is perhaps the easiest to obtain and a close reading of the introductory materials will help you identify a number of his personal prejudices and work around them.

Other Roman recipes

• Carrots Apician 
• Hazelnut Saffron Sauce
• Herbed Barley
• Melon Salad
• Minted Cucumber Salad
• Mushroom Patina
• Roman Sausages with spelt and pine nuts.
• Sauce a la Matius

Other vegetable recipes

• Armored Turnips
• Chard Pie
• Genovese Tart
• Lentil Cucumber Salad
• Marinated Mushrooms ala May
• Onions in Sauce