That is an interesting book with many appealing recipes, but like a number of specialized books, you really have to buy into the author’s theme to make full use of it. Feuer says she uses a commercially processed mixture of peach, pear and pineapple juice that has been concentrated. She buys it 1,500 pounds at a time for use in The Ranch Kitchen Bakery in Montana. For those with non-commercial aspirations, she suggests buying frozen concentrated apple juice, bringing it to a boil and simmering for 10 minutes, to get the right consistency and concentration of natural sugars (or mixing orange and apple juice concentrate and boiling them down).
Feuer also says when adapting a regular recipe to her method, she cuts the amount of sugar in half and replaces that amount with the fruit sweetener. So if you want to skip the fruit sweetener business altogether, you could substitute granulated sugar and double the amount of sweetener called for. Feuer considers her method, however inconvenient it might be, to be a method of reducing the amount of refined sugar one consumes, and considers that to be of substantial benefit.