Serious Eats
Ingredients
1 large egg yolk
1/4 cup packed fresh basil leaves
2 tablespoons finely grated parmesan cheese
2 anchovy filets
1 tablespoon water
4 teaspoons freshly squeezed lemon juice from 1 lemon
1 teaspoon freshly minced garlic (about 1 medium clove)
1/2 teaspoon Dijon mustard
3/4 cup olive oil
1/4 cup extra virgin olive oil
Kosher salt, to taste
Method
Place egg yolk, basil, parmesan, anchovies, water, lemon juice, garlic, and mustard in the work bowl of a food processor fitted with a steel blade.
Pulse until basil is finely chopped and all ingredients are thoroughly combined.
With motor running, slowly drizzle in oils through feed tube.
Season with salt to taste.
Use immediately or transfer to an airtight container and store in refrigerator for up to 5 days.