For our latest experience, we dined in and were glad that we did so. First off, the server was very knowledgeable about vegan options and helped guide us. We had the minestrone soup as an appetizer, which is vegan without any modifications. We also had the Roasted Grapes, which were amazing. Grapes were roasted in olive oil and some salt, and served with micro basil. The grapes were also served with a wheel of vegan cheese, a very nice touch. (Update 5/8/19: we're told the vegan cheese wheel didn't make it onto their regular menu and is not available.)
This time, we ordered the Mama Lou pizza modified to be vegan. This is a vegetarian pizza: asparagus, leeks, oven roasted tomatoes, onion and rainbow Swiss chard. To make it vegan, we had to swap out the white sauce for olive oil and use the vegan cheese. This was a very tasty pizza as well.
We love Basil and we feel like they are only going to get more vegan-friendly as they develop. They have a nice wine menu (with lots of options by the glass) as well as cocktail and beer menu.
We really enjoyed Basil and plan to be back again. And again. And again!