First select all the ingredients, wash them well and then chop them. Place the onion, paprika, leek and garlic in a blender.
Add the cilantro, parsley, oil and water to the blender. The smaller the ingredients are chopped, the easier it will be to blend. Start blending a little at a time.
When these ingredients are somewhat mixed, add the mayonnaise, mustard and other ingredients. Continue mixing to incorporate the new ingredients.
When you finish blending and observe that there are no lumps, the sauce is ready.