Crème d’Orange filling:
6 TB unsalted butter
1 2/3 cups granulated sugar
2 eggs
2 egg yolks
Grated rind of 1 orange
1/4 cup strained orange juice
1 TB orange liqueur (Jim used pure orange extract, but if you have Grand Marnier in the house . . .)

Place all ingredients in a 6 cup non-reactive saucepan and beat with wire whip over low heat or not-quite-simmering water, until mixture thickens like honey. When it is cooking properly, the bubbles that first appeared on its surface as it is heated will begin to subside, and if you look closely you will see a little whiff of steam rise; it will be too hot for your finger. You must heat it enough to thicken, but overheating will scramble the eggs.

Set saucepan it cold water and beat for 3- 4 minutes until filling is cool.

One cup of this is placed between the cake layers.

Crème au Beurre a l’Orange icing:

To the remaining Crème d’Orange filling, gradually beat in 1 stick of softened butter.  The mixture should thicken into a smooth, mayonnaise like cream. If it looks grainy, beat in more butter a tablesppon at a time. Chill until firm but still of spreading consistency. Be sure cake is THOUROUGHLY cold before icing.
Probably when I do this next time, I’ll use the entire filling recipe and turn it into icing using about two sticks of butter.