Combine shallots, vinegar, water, and half the tarragon in a small saucepan. Simmer until reduced to about 1 tablespoon.
Strain the mixture and allow it to cool slightly.
Whisk egg yolks and lemon juice in a heatproof bowl until lightly thickened.
Set the bowl over simmering water, whisking continuously until the yolks begin to thicken.
Slowly drizzle in the warm clarified butter while whisking constantly to form a smooth, glossy sauce.
Mix in the remaining tarragon, parsley, salt, pepper, and cayenne.
Serve immediately over steak, chicken, vegetables, or seafood.
