Please be careful! Margarine-like products are terribly, terribly unhealthy. It is so bad for you that in Denmark, it has become illegal to sell as a food, any product with over a certain percentage of these hydrogenated fats. Please G-d, that will come here because right now the consumption is high, considering the fact that it is in a very large percentage of baked goods, crackers, certain ice creams, etc.
Their artificial molecular structure seem to not get along with our bodies at all. They contribute to artery-clogging and other diseases as well.
Yes, you can make cookies with oil. And on Shabbat, I had a cake made with only olive oil! So, experiment. It’s a good investment in your health.