1 pound frozen strawberries
1/2 cup lukewarm water
1/4 to 1/2 cup (50 to 100 g) granulated sugar (or more)
1/4 teaspoon kosher salt
Place the frozen strawberries, water, 1/4 cup (50 g) granulated sugar and salt in a medium-size heavy bottom saucepan. Add more sugar for a sweeter puree.
Place the saucepan over medium heat and cook, stirring occasionally, until the mixture is bubbling. Allow to continue to cook until the strawberries are softened enough to be crushed by pressing them on the side of the saucepan with a spoon and the mixture has just begun to reduce a bit. Remove the pan from the heat. If you have a stick blender, use it to puree the mixture completely while it’s still in the saucepan. If not, allow the mixture to cool a bit and puree it in a regular blender. Be sure you have enough head space in the blender as hot ingredients will expand quite a bit during blending. Blend in batches if necessary. This is the strawberry puree. To finish here, transfer the puree to a heat-safe jar (a mason jar works well) with at least a 3 cup (24 fluid ounce) capacity. Let the jar sit uncovered until cooled, then cover and store in the refrigerator for up to 2 weeks.
To make a thicker strawberry syrup, return the mixture to the heat (and to the pan if you’re removed it to blend), add about another 1/4 cup (50 g) granulated sugar, or to taste. Cook, stirring very frequently, until the mixture has reduced by about half (at least another 5 minutes). It will bubble up at first, so continue to stir until it settles. The mixture will also become darker in color, and nearly twice as thick, but will continue to thicken as it cools. Transfer the syrup to a heat-safe jar (a mason jar works well) with at least a 1 1/2 cup (12 fluid ounce) capacity. Let the jar sit uncovered until cooled, then cover and store in the refrigerator for up to 2 weeks.