We all know that the way we cook onions and other vegetables will change the way that they taste, but studies have shown that the way you cut your onions has a tremendous impact as well. Slicing your onions from pole to pole will result in less pungent and less flavorful onions for whatever dish you are making.
Instead, try to cut your onions across and parallel with the equator. This will greatly improve not only the aroma of the onions, but the taste as well. For specific dishes, such as chili or curries, this can greatly impact the result of the dish.
Cool Tools – The Science of Good Cooking