In the top of a double boiler, melt the butter with the chocolate.

Place the chocolate in the top of a double boiler set over simmering water.

Transfer to the top of a double boiler set over gently simmering water.

Place the chocolate in the top of a double boiler.

Put the egg yolks and sugar into the top of a double boiler.

Combine all the ingredients in the top of a double boiler.

Melt the white chocolate in the top of a double boiler and transfer it to a small bowl.

Put the chocolate in the top of a double boiler over hot water, stirring often.

Combine the chocolate, sugar and butter in the top of a double boiler.

Then force the mixture through a fine sieve into the top of a double boiler.