Makes:6 to 8 servings
Strawberry is a classic fruit leather flavor: It’s sweet, it’s summery, and, unfortunately, it’s often made cheaply by blending apples with the strawberries. We stick to just strawberries in our version for a pure berry flavor—no other filler fruits to tone down the strawberry taste.
Heat the oven to 170°F and arrange a rack in the middle. Line a rimmed baking sheet with a silicone baking mat and place it on a flat work surface; set aside.
Set a fine-mesh strainer over a medium saucepan; set aside.
Place the strawberries, sugar, and salt in a blender and blend on high speed until you’ve got a very smooth purée, about 1 minute. Pour the mixture through the strainer into the saucepan and, using a rubber spatula, scrape against the inside surface of the strainer to push the purée through until only mostly seeds remain. Remove the strainer and discard the seeds.
Place the saucepan over medium heat and cook, stirring occasionally with a rubber spatula and scraping the sides and bottom of the pan, until the mixture starts to bubble around the edges. Reduce the heat to medium low and simmer, stirring occasionally and scraping the sides and bottom of the pan, until the mixture thickens slightly and reduces to about 1 3/4 to 2 cups, about 15 to 20 minutes. Remove the pan from the heat and stir in the lemon juice. Transfer the mixture to a heatproof container with a spout or return it to the cleaned and dried blender pitcher.
Slowly pour the mixture onto the baking mat, tracing the inside of the colored border to create a rectangle. (If your baking mat has no border, leave a 1-inch border from the edge.)
Pour the remaining mixture within the borders of the rectangle in a zigzag pattern (do not pour it all into the middle of the baking mat). Using the rubber spatula, push the mixture to cover any empty parts within the rectangle (the surface will not be even).
Keeping the baking sheet on the work surface, grasp the edges of the sheet—pressing against the exposed border of the baking mat with your thumbs—and gently shake back and forth to even out the surface of the mixture, rotating the baking sheet and shaking as necessary.
Place in the oven and bake until the surface of the fruit leather is slightly sticky to the touch but, when pressed in several different places, a finger does not leave an indentation, about 5 to 7 hours. Remove the baking sheet from the oven, place on a wire rack, and let cool completely.
Set aside a 16-inch-long sheet of waxed or parchment paper. Starting at one short edge of the cooled fruit leather, pull it up from the baking mat and transfer it to the paper. Using clean kitchen scissors, cut through the fruit leather and paper to form the desired-size strips, shapes, or pieces and then roll them up, paper and all (to prevent sticking). Store in an airtight container for up to 3 weeks.