Hollandaise sauce is a delightful addition to a brunch or dinner menu, but preparing the sauce takes time, patience and some experience. If any of those are at a premium, try making a mock hollandaise sauce with mayonnaise instead. Traditional hollandaise sauce takes time to prepare because the chef must slowly emulsify the ingredients to create the creamy sauce. This method is quicker because the mayonnaise, which is already an emulsion, provides the sauce with the stability it needs to come together quickly. While this sauce isn't as rich and buttery as a homemade hollandaise, it is a good substitute in a pinch.
Whisk together 3/4 cup of mayonnaise and up to 1/2 cup of milk in a small saucepan. Add the milk slowly, stopping when the mayonnaise is thinned out slightly but still has a creamy texture. Place the uncovered saucepan on the stove over low heat.
Stir the mayonnaise mixture constantly for about a minute. Slice a lemon in half and squeeze half of it over the sauce, being careful not to drop any seeds into the pot. Stir to combine.
Add a pinch of salt, a pinch of pepper and a small pinch of turmeric to the sauce. The turmeric gives the sauce a richer flavour and a yellow colour, similar to that of traditional hollandaise sauces that contain egg yolks and butter. A small pinch of turmeric (equal to 1/8 teaspoon or less) is all that's required. The spice can overpower the sauce, so be careful.
Heat the sauce all the way through, stirring it constantly. Season to taste with salt and pepper and serve immediately.
If the sauce isn't rich enough, try adding about a tablespoon of melted butter to the mayonnaise and milk. This will make the sauce greasier, and it may separate upon cooling.