Brackleberry Jam

Ingredients

• 2 cups lightly packed, chopped fresh strawberries (see Cook's Note)
• ½ cup fresh blueberries
• ½ cup fresh blackberries
• ½ cup plus 1 tablespoon granulated sugar
• 1.5 tablespoons fresh lemon juice
• 1 small pinch kosher salt

Instructions

1. Place a small plate in the freezer to chill.
2. In a medium saucepan over medium-high heat, combine the strawberries, blueberries, blackberries, sugar, lemon juice, and salt and bring to a strong boil, stirring to dissolve the sugar. Continue boiling for 5 minutes to soften the berries. Remove from the heat and, using a large slotted spoon or handheld potato masher, mash the berries thoroughly. Return to medium-high heat and continue to boil until the mixture is reduced and slightly thickened, just verging on a jammy consistency, 15 to 18 minutes longer.
3. Remove the plate from the freezer and drop about 1 teaspoon of the jam on it. Wait about 15 seconds and then run your finger through the jam. If it leaves a clean trail, the jam is done. If the jam runs back into the trail, return the plate to the freezer, turn the heat to medium, simmer the jam for 2 to 4 minutes longer before retesting. When the jam is done, transfer it to a heatproof jar and set aside to cool to room temperature (it will thicken as it cools). Cover with a tight-fitting lid and refrigerate for up to 3 weeks.