Bring a medium pot of salted water to a boil.

Blanch basil leaves in hot water for 30–40 seconds. Remove basil from water and plunge into ice water to stop the cooking process. Dry the basil on paper towels as much as you can.

Place basil, mayonnaise, and lemon juice into blender. Blend on high, scraping down the sides of the container as necessary, until the mayo is pale green and the basil is incorporated. (You will have more basil mayonnaise than needed. Keep stored in an airtight container in the refrigerator for up to 2 weeks. Spread freely on anything you desire!)