Rinse the basil leaves and pat them completely dry, since wet basil dilutes the flavor of your dressing. Peel the garlic cloves and roughly chop the shallot so they blend evenly. Having everything ready before you start keeps the process quick and mess-free.
Add the basil, garlic, shallot, olive oil, vinegar, salt, and red pepper flakes into your blender. Blend on high for about 60 seconds until the mixture turns smooth and vibrant green. Stop and scrape down the sides once if needed for an even consistency.
Once blended, give the dressing a taste before serving it. I usually add a little extra salt or a splash more vinegar depending on how sharp my garlic is that day. This is the step where you really make the recipe your own.
You can use the dressing right away while it's fresh and vibrant, or transfer it to a jar and pop it in the fridge to chill for later. I like making a batch in the morning so it's ready to drizzle over dinner that night.