Fist Full of Jam is a FruitFoodItem cooked in a Crock Pot by adding any Fruits except Dragon Fruit, which will lead to a Dragonpie instead. However, adding more than 2.5 units of Fruits may result in Fruit Medley instead. It takes 10 seconds to cook.
Fist Full of Jam does not exclude Fishes. Shipwrecked DLC introduces food items that have fish values without any meat value, such as Fish Morsel and Jellyfish. This causes using up to 2 Fish Morsels or using a single Jellyfish in a recipe with Fruits to produce Fist Full of Jam despite containing meat.
Tips
Making Fruit Medley is a more efficient use of Durian Fruit by adding a stick instead of a fourth fruit, getting much more healing, more sanity, and slightly more hunger return per fruit.
You can put 3 berries and a Durian fruit to get this item, which results in the same hunger and health bonus as just the berries (roasted), but slower rot time and 5 sanity added.
Eating the individual ingredients cooked is almost always better than using them to make Fist Full of Jam, unless the player needs the small Sanity boost or needs to keep the food longer. Jam keeps for 15 days, compared to Berries' 6 and Roasted Berries' meager 3.
Another possible reason to do this is to freshen a pile of Berries to be effective whilst using Wickerbottom. This works with spoiling Berries, meaning the player can gain Sanity and the full amount of Hunger