Toss the strawberries in a medium sauce pot with the sugar, jalapeño, lemon juice, lemon zest, cinnamon, and salt, and let sit at room temperature for 1 hour or until the strawberries are soft and juicy.
Place a plate in the freezer. Add the water to the pot, then turn the heat to high and bring the pot to a boil.
Turn the heat under the saucepan to medium-high and smash the berries with a masher. While occasionally stirring, cook until the jam has thickened or has reached a temperature of 220°F, about 15-20 minutes. (As it cooks, the jam will get foamy but that’s normal.)
To test if the jam has been set, place a spoonful of it on the plate that’s been in the freezer. After a few seconds if the jam doesn’t run it’s ready.
Pour the jam into the prepared jars and refrigerate. It will keep for 1 month.
