This is the most simple recipe you'll ever do! Thimbleberries are so delicious you don't want them to go to waste. Try this super simple jam recipe with less sugar than the other ones you'll find to let the berry flavor really stand out.
Rinse and search the thimbleberries for any bugs that might have snuck in while you picked them.
Put jars and lids in a large pot and cover with water. Bring the water to a boil and let it continue to boil while you cook the berries.
Add thimbleberries and sugar into a pot and set the heat to medium-low. Stir constantly until the berries let out their juices.
When the berries have released their juices add lemon juice and turn the heat up a little to medium/medium-high. Bring the mixture to a boil. Stir often so the berries don't stick to the bottom of the pan.
Boil for about 3 minutes and then pour jam into jars.
Process the jars for 10 minutes. Allow to cool and then store in a cool, dry place.