related but not alike. shallots are a small bulb like an onion but spliting into smaller segments like garlic - also tasting somewhere between onion and garlic. leeks are a thick stem like an overgrown spring onion. they are fibrous and need cleaning and cooking. milder than onions they have an earthey flavour that penetrates and works with other root veg and herbs.
Endive, shallots, fennel, and leeks
Depending on the recipe, you can use onions or green onions in place of leeks. It won't be identical but it can be close.
Onions are the edible bulb from a genus of plants called Allium. Onions are a vegetable and are related to garlic, shallots, leeks, scallions, chives, and green onions (underdeveloped scallions).
Some people may say that onions or shallots are a good substitute, but be careful: they may give a strong unwanted flavour where a more subtle flavour would have been better.
http://www.newton.dep.anl.gov/askasci/gen06/gen06199.htm this website is helpfull with understanding what foods have sulfur in it
While leeks could potentially be used in the sales of fast food, it seems unlikely. Leeks are similar to onions, which are cheap and easy to prep. Leeks are more expensive, and require extensive preparation and washing, so it is unlikely that we will see their use in fast food anytime soon.
Asafoetida is the dried gum from the stem of a small plant grown in India. The sap is similar to latex. It has a flavor similar to leeks.
Leeks are the closest in taste if not also texture, they do have a mild flavor.
The Tagalog word for shallots is "sibuyas Tagalog" or "sibuyas dahon."
Shallots are sweeter and milder relatives of the onion, sort of in the way that a yam is related to the potato. http://en.wikipedia.org/wiki/Shallots
Welsh leeks may be larger or smaller than leeks grown elsewhere, but leeks are leeks.
shallots are mini onions mostly used in making sambhar.