Arguably no group loves walnuts more than Georgians, who add them to almost any dish. This ardor manifests itself in dozens of walnut sauces, the original concept adapted from Persian cuisine, which are served with almost everything. The most versatile of these sauces is bazha. Typical of Georgia, this uncooked sauce is slightly tart as sweeteners are not used in cooking. The thickness of bazha varies according to the nature of the dish: a thicker sauce for pkhali (salads); a thinner sauce for poultry and fish.
Using a mortar and pestle or a food processor, grind the walnuts, onion, garlic, and salt into a paste.
Stir in the vinegar, cilantro, coriander, cayenne, turmeric, and fenugreek. Add enough water to make a sauce with the consistency of heavy cream.
Let stand at room temperature for at least one hour. The sauce will thicken as it stands. Cover and refrigerate for up to three days. If too thick, stir in a little more water.