Béchamel, Espagnole, Hollandaise, Mayonnaise, Tomato Sauce, and Velouté are the mother sauces of French cuisine. We also have added Beurre Blanc which isn't officially a mother sauce, but it also is a solid base other sauces are built from. Once you know how to make these you can add a few different ingredients to each base to make 100's of different variations.
Beurre Blanc, or Butter Sauce as we said isn't officially one of the mother sauces, but as I said it is a base you can build many interesting, and easy sauces from.
In cooking, Beurre blanc—literally translated from French as "white butter"—is a rich, hot butter sauce made with a reduction of vinegar and/or white wine and shallots into which cold, whole butter is blended off the heat to prevent separation. (Lemon juice is sometimes used in place of vinegar and stock can be added as well). This sauce originates in the Loire Valley cuisine.
It is not uncommon to see recipes that include a beurre blanc sauce to which heavy cream has been added as a "stabilizing agent". This is a point of contention amongst many culinary enthusiasts and can be heavily frowned upon. To be precise: Adding heavy cream to beurre blanc turns it into beurre nantais (Nantes butter) which is a variation of the mother sauce and not the base.
2 tablespoons shallots, finely minced
1/4 cup white wine or dry vermouth
1/4 cup freshly squeezed lemon juice or white wine vinegar
4 ounces unsalted butter, cut into pieces
Salt to taste
White pepper to taste
In a non-aluminum saucepan, combine shallots with the wine. Reduce a glace (until syrupy). Add the lemon juice or vinegar and reduce a glace. Remove from heat and add one chunk of butter, stirring with a whisk to blend. Slowly add all the pieces of butter until well combined. This technique is called monter au beurre, to finish, or "mount" a sauce with butter. If you need to return the sauce to the heat to incorporate all the butter, do it over very low heat, or the sauce will break.
Strain the sauce through a fine mesh strainer and serve immediately, or hold in a double boiled over barely simmering water, or in a Thermos.
You can go anywhere from this basic beurre blanc, with endless variations -- herbs, onions, fruit juices or purées, soy, chiles ... your imagination is the only limit.
Ray's Boathouse BoPo and Fire Butter
If you have ever been to Ray's Boathouse, and had some steamed clams you probably have noticed that the butter dipping sauce is quite incredibly addictive. Well it is high grade 100% butter that has been melted down, and separated, then it is recombined, and whipped with a whisk to make the creamy sauce. When you melt butter it separates into 2-3 components. The first is the Salt, next is the clarified butter which is oil, the last is the Whey which is white, and creamy.
To make this you need to be willing to melt at least a pound of butter. If you use salted butter you skim off the salt which is at the very top first. Next you ladle off all the clear, or clarified butter. Once you have the butter separated you slowly mix back in, while whisking, the clarified butter, into the Whey. This is what they call an Emulsion, and that is what you are creating. You don't add all the clarified butter back in, or it is going to break, so you need to find a use for the additional 1/4 of clarified butter remaining. One idea is you can mix it with garlic throw it on some bread, or use it to make a little Hollandaise.
This is also a good basic sauce to flavor with some Citrus, or Tabasco. Patrons of Ray's Boathouse often ask for Tabasco to spice up their Chowder, or BoPo to create what they call Fire Butter.
Compound Butters are excellent, go great with Fish, and are very easy to make from whatever ingredients you have in the vegetable, or fruit drawer. For halibut I like to mix a little fresh Orange, Lime, and Lemon Juice with cold Buttter. I then re-refrigerate the butter and serve sliced on the top of the cooked fish, or vegetables. As it melts it turns into a savory, creamy sauce.
The whole idea on any type of compound butter, or Beurre Blance is to do it at low heat so the butter does not separate.