Step 1

Place 1 tablespoon freshly grated lemon zest, 1/4 cup freshly squeezed lemon juice, 1/2 cup grated Parmesan cheese, 1 tablespoon Dijon mustard, and 3/4 teaspoon freshly ground black pepper in a blender. Blend until smooth, about 20 seconds.

Step 2

With the motor running, remove the inner cap on the lid and slowly pour in 1/4 cup olive oil. After adding all of the oil, continue to blend until creamy and emulsified, about 30 seconds more.