Yes and no - you want to cook them to between 120 and 180 degrees celsius to cause them to brown, which is usually done with oil in a pan.
You can also oil things and roast them (roasted garlic for example) in an oven to get the right browning/caramelization reaction.
Oil is used because it can be heated above 100 degrees (unlike water) and because charring food is quite difficult to do without burning it (except for corn which is very easy to char properly).
Yes and no - you want to cook them to between 120 and 180 degrees celsius to cause them to brown, which is usually done with oil in a pan.
You can also oil things and roast them (roasted garlic for example) in an oven to get the right browning/caramelization reaction.
Oil is used because it can be heated above 100 degrees (unlike water) and because charring food is quite difficult to do without burning it (except for corn which is very easy to char properly).