When making beurre blanc, start by creating the au sec from your shallots, white wine vinegar, and dry white wine. You should have less than a tablespoon of liquid left before adding the cold, cubed butter. The butter should be added off heat or on low heat to help keep the emulsion from breaking. Add it a bit at a time while whisking vigorously — you should not see any fat droplets. When it's evenly mixed, add a little more butter. The more sauce you create the faster you can add the butter, but wait until it's all mixed in before adding more. When you're done, quickly strain it (ideally into a warm container) to remove the shallots, and serve it immediately. It should be fairly thick and very even. If you see any droplets of fat, it wasn't emuslified properly. If you practice once or twice you should be able to get it down. It's much less temperamental than Hollandaise.

Note: If you're having trouble starting your emulsion — or if you reduce the initial wine / wine vinegar too much, you can add a tablespoon or so of water before adding the butter. This will make it a bit easier to start the emulsion. (This is similar to how beurre monté is made.)

Chef Michael