Mirabelle plum jam. Very ripe, Put the plums, dressed and rinsed in a saucepan (possibly with the addition of a few tablespoons of water) and overcook it. Then rub through the colander, Cook (on an asbestos plate) until thickened, stirring often. Then add sugar to taste (they should be acidic) and continue to cook, until the mass thickens like this, that it will fall off the spoon in pieces. Put hot jam in jars or bake in stoneware. Mirabelle plum jam is suitable, among others, in. for various pastries, e.g.. for translating mazurkas or cakes.