In a food processor, blend the mashed avocado and lemon juice until smooth, stopping to scrape down as needed. Add in minced garlic and basil and blend until smooth. Be patient as this should take a few minutes, but you will be rewarded with super smooth and creamy pesto. If you need to add a tablespoon or two of almond milk to help the blending along, you should do so at this step. Salt to taste, serve as you wish.