I chose to use fresh baby san marzano tomatoes for this (they sell them at trader joe's), but you can also use cherry or grape tomatoes, or even some baby heirloom's! (plvnt.com)
To the final soup, I included some chopped carrots and celery with the onion and garlic and ended up using a large can of san marzano tomatoes which I crushed and cooked down as directed. (epicurious.com)
I just need to figure out what I did wrong to make it so oily, I did blend the San marzano tomatoes cuz I don't love chunkychunky sauces that much. (epicurious.com)