Put the milk and oil in a blender jar (with soy milk it becomes a vegan mayonnaise). The higher the oil content, the more solid the whole thing will be. Salt, pepper and mustard (anything from sweet to lion mustard) with it. Add a pinch of sugar. Put the hand blender in, place it on the floor, pull it up slowly at full power. Then you can add all the other ingredients as you like. E.g. garlic (makes aioli), herbs, curry, cognac (makes cocktail sauce) etc. - give it a try! Tip: With lots of herbs, chopped cucumber and chopped egg (+ garlic?) It becomes a wonderful tartar sauce! In any case, add: acid (vinegar and / or lemon juice). Only after pureeing, because otherwise the milk would curdle.