My research so far indicates that cats indeed cannot taste sweet. Many types of cat food contain sugar nontheless, mostly as preservative and to give it a (for humans) tasty looking brown color.
Your post lets me assume that you are well aware that some common ingredients in human food are toxic to cats. Avoid feeding any of those, even in small quantities.
It's the protein that influences the taste of food most for cats. Since cookies usually don't contain meat, I doubt it's the taste attracting your cat.
There could be a number of different reasons why your cat wants some of the cookies.
- It might be simple curiosity. You are putting human-kibbles into your mouth and your cat recognizes that you're eating them. So she wants some, too. Especially the crunchy sound of cookies might wake her interest, since it sounds quite like a cat munching on a mouse, including bones.
- She might be expecting different food. Cats are very intelligent and know that people sitting at tables and the clatter of cuttlery on porcelain means that there's food nearby. Maybe she hopes for a piece of meat and gets sweets instead.
- She might like the texture of those foods. Cakes and cookies have very different textures, so I'm not sure about this one.
- The act of sharing food is a sign of love for cats (That's why many cat owners find half-eaten mice or birds parked on the doormat). She might expect the same gesture from you, even if your gift doesn't taste as good as hers.
- She might not be asking for food at all, but for pets. Maybe she associates your eating cookies with being caressed and with social interactions in general. If you usually sit down to eat any of these, she has a perfect opportunity to interact with you.
- Maybe there actually is something in those cookies that tastes good to her.