She did say that there's a fat replacer recipe in the McDougall Newsletter Archives, November 2008. Just ignore the Lighter Bake recommendation.
Now that Wonderslim Fat & Egg Replacer is no longer being manufactured, I have received many questions about what to use instead of that product in baked goods.
There is still one product available that is quite similar, Sunsweet Lighter Bake. If you can’t find this in your local markets, it may be purchased online at www.sunsweet.com.
(Click on Store, then go to Gourmet Pantry, then to Baking Mixes where you will see Lighter Bake.)
Baby food prunes also make a good substitute. Or you can make your own Prune Puree for use in baked goods. Place a 12 ounce package of pitted prunes in a food processor and add about ¼ cup of water. Process and slowly add more water while processing to reach the desired consistency (between 1 and 1½ cups). It should be about the consistency of soft applesauce. This can be stored in the refrigerator for several weeks.
Other possible substitutes for oil in baking are applesauce, pureed tofu or ground flaxseeds (remember that tofu and flaxseeds do contain some fat, however).
She did add in the lecture to use half the amount of the prunes as the amount of oil called for in a recipe, so if it reads to use a half cup of oil, use 1/4 cup of prune puree. Got it? Will you remember when the time comes? I know I won't. LOL