If using frozen strawberries, let thaw. Puree the berries in a food processor or blender (or with an immersion blender) until smooth.
In a small bowl, combine two cups of puree (if there is any left, use it for a sauce or smoothie) and the applesauce.
Taste the mixture: If you use unsweetened applesauce, you may want to add some sweetener, a tablespoon at a time, to the mixture for taste.
Pour the mixture into a Gefen Parchment Paper lined 10×15 inch baking sheet.
Place in a 200 degrees Fahrenheit oven for four to six hours. When done, the mixture will no longer be tacky to the touch, you will not leave a fingerprint, and the fruit leather will pull away from the parchment easily. Slice into rectangles (a pizza or pastry wheel works well) and roll up.