http://www.simplyrecipes.com/recipes/orange_beurre_blanc_sauce_for_seafood/
Zest half of one orange (about 2 teaspoons) and juice the two oranges (about 3/4 cup). Put the juice, zest, wine and shallots in a sauce pan on medium high heat. Cook until it is syrupy and almost gone.
On low heat, whisk in the butter continuously and vigorously, 1 tablespoon at a time. Butter is the only emulsifier for this sauce, and if you slowly add it, continuously stirring, the sauce will achieve a silky smooth texture. Do not let the sauce boil.
Add salt and pepper to taste.