In a heatproof bowl whisk egg yolks with 1 tablespoon of the lemon juice until thick and pale. Set bowl over a pan of barely simmering water, stirring constantly, until warm but not hot. Stir in butter, a few tablespoons at a time, until all butter is incorporated. Cook, stirring, until sauce thickens enough to lightly coat back of a spoon. Remove from heat and stir in remaining lemon juice, Tabasco, salt, pepper and cayenne, to taste. Fold in tomatoes.
Yield: About 2 cups