In a small non-aluminum saucepan, combine the orange juice and 1teaspoon of the sugar. Bring to a gentle simmer over moderate heat and cook until the juice is reduced to ¼cup, 5 to 6 minutes. Remove the saucepan from the heat and set aside to cool.
Combine the orange zest, the remaining ¼cup sugar, and the egg yolks in a mixing bowl. Whisk until the yolks turn pale. Add the reduced orange juice and whisk until blended.
Set the bowl over a saucepan of gently simmering water and stir until the mixture thickens enough to coat the back of a wooden spoon, 6 to 8 minutes. Stir in the butter until melted. Quickly strain the cream through a fine-mesh sieve. Chill the orange cream, uncovered, in the refrigerator until cool, 30 to 40 minutes.
Store the orange cream airtight in an impeccably clean container in the refrigerator. It will keep for up to 1 week.