A sure fire way to add flavor to a recipe, especially a soup recipe, is to start with a Mirepoix. A mirepoix is a fancy way to saying onion, carrot and celery. Regardless of what you call it this practice is a great way to infuse a vegetarian recipe with a ton of flavor.
I am going to start by showing you best I can how to easily and safely dice the onion, carrot and celery. You can also purchase these items pre-diced at stores like Trader Joe's, but I highly recommend dicing them your self. If nothing else the practice will help with your overall knife skills. First you need a sharp knife and a non-slip cutting board. I use Pampered Chef cutting boards and I swear by them. They have rubber around the edges and they do not slip while you are cutting on them.
Start by cutting the onion in half, remove the out skin (save it to use later in broth) and cut off the top of the onion where it tapers, but keep the bottom intact so that the onion stays together while you cut it.
Hold the onion, with you fingers well clear of the blade, and slice the onion horizontally upwards towards what was the bottom of the onion
Again, while keeping your fingers well out of the way, now cut the onion vertically.
Now cut down into the onion towards the cutting board, leaving a nice diced onion. Repeat with the other half of the onion if your recipe calls for the entire onion.
Cut the peeled carrots (save the peelings for broth) into strips and then turn and dice
Cut the tops and bottoms of the celery (save for broth), cut the celery into strips and dice.
Saute the onion, carrots and celery in melted butter or olive oil