Mix all ingredients together and allow to simmer until the strawberries have completely thawed. Turn the heat up to medium-high and allow it to boil until the apples are soft and the berries have lost their shape. Mash the fruit a little to make the mixture more uniform and continue to cook until the jam thickens. Cool and serve (or use in the Strawberry-Custard Tarts recipe to follow). Makes 2 cups.