Bearnaise Gramma's Recipe

Combine white wine, vinegar, shallot, tarragon, and black pepper together in a saucepan; bring to a boil. Reduce heat and simmer until mixture is reduced to about 1/4 cup, 5 to 10 minutes.

Whisk egg yolks, hot water, salt, and hot sauce together in a bowl until very well mixed, about 2 minutes.

Pour white wine mixture into the top of a double boiler over simmering water. Whisk egg yolk mixture into wine mixture until well mixed. Pour butter into mixture and whisk until sauce is smooth and thickened, about 5 minutes.