Sunday sorpotel on a Goan veranda.

The invitation, relayed through a cousin, was for Sunday lunch, and the instruction was to arrive at one and not before. I arrived at twelve-forty because I am from Bombay and cannot help myself, and was given a beer on the veranda and told, politely and unmistakably, to sit down and stop being early.

Sorpotel is pork — shoulder, liver, and, if the household is orthodox about it, blood — cooked with vinegar, feni, dried Kashmiri chillies, and a spice paste that every family grinds slightly differently and every family believes is the correct one. What makes it a Sunday dish is not the cooking, which takes an afternoon. It is the resting. It is cooked on Thursday, reheated Friday, reheated Saturday, and eaten Sunday, and the vinegar does its work across those days in a way that cannot be shortcut. “Sorpotel is better on the third day,” Maria Fernandes told me, in the tone of someone stating the boiling point of water. In that house it is not an opinion. It is a rule of the calendar.

Sorpotel is better on the third day. This is not an opinion in that house; it is a rule of the calendar.

The house is in Assagao, one of the old ones, with a red laterite plinth, a balcão at the front and a veranda at the back that looks into a garden with three coconut palms and a large amount of unbothered vegetation. Her parents-in-law bought it in 1958. The kitchen has been rebuilt twice and the argument about the spice paste has been running for the entire duration.

The argument, for the record, is about the vinegar. Her mother-in-law used only coconut toddy vinegar, which is milder and cloudier and now inconvenient to buy. Maria uses toddy vinegar cut with a little cane. Her daughter, who was there and who cooks it in Lisbon, has views involving a third vinegar that were not, on the day, given a fair hearing. It was conducted with great warmth and no prospect whatsoever of resolution.

The rest of the table: sannas, which are steamed rice cakes fermented with toddy and are the only correct thing to eat with sorpotel; a prawn balchão of considerable violence; a salad of onion, tomato and lime that exists to give your mouth somewhere to go; and bebinca, which took someone four hours and sixteen layers and was gone in about nine minutes.

The house takes two sets of guests at a time, in the two front rooms, and Sunday lunch is included if you happen to be there on a Sunday. Maria was clear that it is not a cooking class and she would prefer you did not film it. You are welcome in the kitchen. You will be given something to stir. You will not be given the recipe in a form you could publish, and after an afternoon of listening to three generations disagree about vinegar, I understood that this is less about secrecy than about the fact that there is no such form.