cinnamon?
Adds flavor...might not be what you're looking for. Cinnamon might be too close to brown...and you may need to use alot of it. I'm BRAINstorming here...hheheheh.
paprika....no...flavor issue, nice color, though. actually, paprika does'nt seem to have much flavor, but I'm not sure if that's what you're going for.
Maybe melt down some of those red gumdrops, and make a syrup to blend into the white frosting. A double boiler might work for that. try mixing in some light corn syrup. Corn syrup may help of any consistancy issues arrise.
This is how I come up with recipes. Whatever I find in the cupboards, work it in somehow.
Slicing a black licorice stick or 2 or 5 might make some interesting black olive parodies.
Beet juice.
Puree some strawberries in the cuisinart. Just enough to blend in, and make that white frosting red. Raspberries might work, too. Consistancy issues might arise in this application, so have more powdered sugar, and vanilla extract on stand by.
Try adding a drop or two of vanilla extract to the a dablet of the frosting you already dyed. Try it with just a dab of the already dyed frosing you have checking flavor compatibility.
Tell Mr. Wipple at the grocery store to find some red frosting for you. I've never seen red frosting....other than what might be found on a decorated cake. For example:The Roses on a wedding cake. NOT TASTY.
My friends at Phizer recommend FDC 40 Red. They use that in their listerine cinnamon breath strips, and I have'nt noticed a metallic taste when using them.
Red paint would be a bad idea.
Tomato puree...but then, you may as well just make it a real sort or pizza, and the big cookie novelty would be gone.
Are we working with a deadline here?...otherwise wait and see what they bring back from Mars. Mars is red.
Consider something tasty, and red. and what you might have to do to make it into a dye sort of thing for your frosting. Keep flavor compatibility in mind.
Cover the entire cookie with sliced strawberries, and work it from there. Strawberries are red.
Finely grated apple peelings.... :? ...maybe not
I wish you success in your quest. I'm sure this one will keep me from getting any sleep until I have figured out the best possible ingredient to turn white frosting red.
Keep me posted, as I really enjoy sleeping.
Brain 8O