In a blender cup or food processor, combine 1 egg, 1/2 teaspoon lemon juice, 1/2 teaspoon vinegar, peppercorns and mustard. Blend Until it begins to thicken slightly. Add 1/4 cup of oil to the blender at a time. Blending fully before adding the next 1/4. The final product should be thick, but spreadable. Season with a bit of salt your desired taste.