This is mostata, also, confusingly, known as mostarda. It is made from grape must boiled up with wood ashes and other ingredients such as raisins and almonds. Each province has its own way of making it. I have to say that I find it leathery and liquoricey so perhaps it is an acquired taste. The Trinacria pattern is a symbol of Sicily.
Korčula Paintings, Part Two
13 hours ago