This is another recipe that I found in that same stack of hand-me-down magazines. I tweaked it to make it gluten free.
SPH Gluten Free Secret Ingredient Cookies
inspired by a recipe by Candace Zaugg
Taste of Home Magazine, February/March 2008
1 box Betty Crocker Gluten Free Chocolate Chip Cookie Mix
1/2 cup butter, melted
2 eggs
1 tablespoon vanilla extract
1 cup shredded carrots (I do mine in the food processor to make them extra fine)
1 cup gluten free granola (I used Jessica's Natural Foods Chocolate Chip)
1 3-oz. package chopped walnuts
Preheat oven to 350. Mix the cookie dough according to package directions. Stir in carrots, granola and walnuts. Drop by spoonfuls onto parchment lined cookie sheet (I use a cookie scooper). Bake for 18-20 minutes. Allow to cool completely, then eat and enjoy!
These would also be lovely dusted with a little powdered sugar if you are so inclined. We just LOVED them plain!
Another variation: use grated zucchini. And the trick with grated zucchini - let it drain in a fine mesh strainer for at least a couple hours before you bake with it. Zucchini is almost all water. By draining it first, the water has a chance to escape before the zucchini gets cooked. No fine mesh strainer? Use some cheesecloth in a regular colander. Works just as well.
Feed a few of these to your picky eater, and tell them the secret ingredient is love.
Have a great day!

Recipe linked to Very Good Recipes