Step 1: First thinly slice the onions. As you do this, melt the butter in a pot, and add the onion as you chop them. Stir the onions frequently and wait for them to become "glassy" as the butter soaks into them (you may need to add more butter here).
Step 3: once they are glassy, add enough stock to cover the onions (as well as any herbs/spices you may want). Then cook for about 10 minutes (while continuously stirring), or until all of the onion pieces are soft.
Step 6: if you want, you can get a slice of bread, usually white slice pan, toast it, add some butter and place it on top of the soup in the serving bowl. You can then take a few slices of cheese (hard cheeses such as cheddar work best) and put them on the bread. Then microwave the whole soup and bread for a few seconds until the cheese melts.
Step 8: enjoy! Onions are cheap, and while butter can be expensive, you could use any kind of fat. It is a relatively quick and definitely delicious recipe!