"Jam mixture" refers to a combination of various ingredients used to make jam, usually consisting of fruits, sugar, and sometimes pectin or lemon juice. Full definition
To prepare ham, combine 2 tablespoons mustard, sugar, 2/3 cup jam, and pepper in a small bowl; spread half of jam mixture over ham. (health.com)
Put one very full tablespoon of cream cheese in the center of each pastry square, add another very full tablespoon of the fruit jam mixture, then add one 2» x 2» - inch square of chocolate. (fieryfoodscentral.com)
Flatten each piece of dough using your hands and fill each with about 1 tbsp of plum jam mixture. (homecookingadventure.com)