Wash fresh fruit, remove and discard the stems and pits*, cut large fruit into pieces. The frozen fruit is good to go straight into the pan. I used 2 cups cherries, 1 cup blueberries, 1 cup cranberries.
Place 2 small plates or bowls into the freezer for testing the jam later.
Combine the fruit, lemon juice, and maple syrup in a medium saucepan over medium-high heat. Stir occasionally until the fruit starts to cook.
As the fruit starts to break down, use a large slotted spoon or potato masher to mash the fruit to your desired jam consistency (smooth or chunky).
Continue to cook over medium-high to high (stirring frequently) until the jam has thickened (~15 minutes). Taste and adjust sweetness as needed. Check to see if the jam is done using the frozen plate test (see recipe notes below).
Remove the jam from the heat and let cool. The jam will thicken more as it cools. Store in a clean glass jar with a lid in the refrigerator.