about 1/2 cup
In a blender or food processor add egg yolks, anchovy filets to taste, Dijon mustard, and lemon juice. Pulse until well combined.
With the blender or food processor running, very slowly drizzle in olive oil drop by drop until emulsified then gradually add vegetable oil in steady stream until completely incorporated. Add parmesan and salt and pepper to taste and briefly blend. Serve immediately.