White Nut-Based Sauces: From Apicius to Modern Mexico
We have just one cookbook from the Roman Empire and it’s always known as Apicius. For a long time the author was thought to be a great gourmet.
No, say Christopher Grocock and Sally Grainger in their invaluable translation. A cook or a series of cooks just jotted down the minimum they needed to remember a recipe. Just an ancient version of those crammed boxes of notes in your mother or grandmother’s kitchen.
That means the manuscript is full of puzzles. One that Grocock and Grainger point to is a white sauce for boiled bird. Apart from the color it has nothing to do with what we often call white sauce, a roux-based sauce made with milk.
Here’s the recipe.
“Pepper, lovage (a herb), cumin, celery seed, roasted hazelnuts or almonds or (any) skinned nut, a little honey, liquamen (like contemporary Thai fish sauce) vinegar and oil.”
No instructions. The cook was supposed to know what to do. In all likelihood he (we’re talking professional cooks here) pounded the spices, herbs and nuts, and then stirred in the liquid ingredients. The puzzle is the phrase “any skinned nut.”
Latin, like Spanish but unlike English, does not have a single word for nut. Here the word is nuces, probably walnuts.
Grocock and Grainger puzzle over how to skin (as opposed to shelling) these nuts. They puzzle about how they could make a sauce that is white.
After all, with the walnuts we normally buy, the skin is glued to the nut and grinding would result in a brownish paste.
I think it can be solved by looking at Mexican cooking. Just look at this photo.
On the left is the kind of walnut you usually buy in the store. Old and dry. On the right is a walnut (often called nuez de castilla or Spanish nuez) sold in a Mexican market. It’s young, fresh, soaked in water, and someone has peeled off the skin while it’s still possible to do so–that is in September just when they ripen. It’s tedious, fiddly work which is why they cost $10 a pound. In short, it’s quite possible to peel walnuts but only when they are super fresh.
And they are sheer delight. They have almost the consistency of water chestnuts, slightly crunchy, almost sweet, with a a very slight and appealing bitterness from any bits of skin you leave on.
They are “gourmet” items in Mexico. And they are used to make a wonderful “white” sauce. The little flyer given out in the San Angel market in Mexico City offers these instructions which I’ve translated.
100 grams of nuez de castilla (walnuts), peeled and without the brown skin
1/2 container of fresh crema (that is, about a cup of creme fraiche)
1 teaspoon of sugar
Salt to taste
Put all these ingredients in the blender and whiz together.
This makes a shining whiter-than-white sauce. It’s spectacular looking and spectacular to eat. Yes, it is possible to skin walnuts if they are young. And yes it is possible to make a white sauce with pounded walnuts.
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Nogada sauce is spooned over stuffed poblano chiles to make one of Mexico’s signature dishes. That’s another story. And so is the question of the connection between the sauce of ancient Rome and the sauce of today’s Mexico.
