This dish calls for Roman mustard, which is a coarse-grained mustard based on Apicius’s recipe.
To make about 3½ cups of Roman mustard, combine the mustard seed, vinegar, and grape juice, and mix in the salt and cumin. Leave to soak, covered but not sealed, for 36-48 hours. Put into a food processor and work for 1-2 minutes or until coarsely ground, then add the almonds and pine nuts and work very briefly until they are completely broken up, not over-processed.
Trim the beans, then slice them into 1-in pieces diagonally. Cook in boiling salted water for 5-10 minutes, depending on their age. They should be tender but still have a slight bite. Drain.
Heat 1 tablespoon of the oil in the empty pan. Blend the chili, garlic, and mustard together with a pinch of salt. Add to the pan and Stir-fry for 30 seconds. Add the beans and stir thoroughly over a very low heat.
In a small pan, heat the remaining oil, add the mustard and cumin seeds, and cover. Cook until they start to splutter. Pour over the beans and serve immediately.
© 1999 Jennifer Paterson. All rights reserved.