1. Puree berries or chopped stone fruit, sugar, and lemon juice. Cook in a saucepan over medium heat until thick, 30 to 35 minutes. Strain through a fine sieve onto a baking sheet lined with a nonstick baking mat; tilt to distribute. (Use a pan that isn't warped to prevent pooling.) Bake at 170 degrees until dehydrated, 2 1/2 to 3 hours. Let cool for 10 minutes. Cut into eight 4 1/2-by-5 1/2-inch rectangles. Roll in parchment. store at room temperature for up to 1 month -- or 2 seconds, depending on your kids' appetites.