Start by placing a small ceramic plate in the freezer. This will help you test the jam’s consistency later. It’s a little trick I learned that makes all the difference!
Next, take 2 cups of blueberries and put them in a high-sided saucepan. Using a potato masher, gently mash the berries to release their juices. This step is crucial as it sets the stage for a flavorful jam.
Add the remaining blueberries to the saucepan along with the lemon juice, lemon zest, and sugar. Stir everything together until the sugar is well incorporated.
Place the saucepan over medium-high heat. Bring the mixture to a boil. Keep an eye on it, as it can bubble over if you’re not careful!
Once the blueberries start boiling vigorously, set a timer for 12 minutes. Continue boiling the berries while stirring frequently. You’ll notice the jam starting to thicken.
As the jam cooks, watch for changes in color and texture. The blueberries will break down, and the mixture will become syrupy.
After the timer goes off, pull the plate from the freezer. Place a small amount of the jam on the plate and run your finger through it. If it jells and seems thick, it’s ready to come off the heat.
If the jam isn’t thick enough, put the plate back into the freezer and continue to cook the jam for a minute or two longer. You can repeat this taste test until you achieve the desired consistency.
Once it’s perfect, remove the pan from the heat and allow the jam to cool slightly.
Divide the jam into clean glass jars. Let them cool for about 2 hours before topping with lids. Once the jam reaches room temperature, store it in the refrigerator and enjoy it within 2 weeks.
