Place the saucepan over medium heat and cook, stirring occasionally with a rubber spatula, until the mixture starts to bubble around the edges. Reduce the heat to medium low and simmer, stirring occasionally, until the mixture thickens slightly and reduces to about 1 3/4 to 2 cups, about 10 to 15 minutes. Transfer to a heatproof container with a spout or return to the cleaned, dried blender pitcher.
Slowly pour the mixture onto the baking mat, tracing the inside of the colored border to create a rectangle. Pour the remaining mixture within the borders of the rectangle in a zigzag pattern 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 sheetâ€”pressing against the exposed border of the baking mat with your thumbsâ€”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 6 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 desired-sized strips, shapes, or pieces and roll up, paper and all.