1 medium orange
1 1/2 cups sugar
3/4 cup butter
4 eggs, beaten
Squeeze 1/4 cup of juice each from the lemon and orange.
In heavy saucepan, combine butter, sugar, and juice. Heat gently until butter is melted. Stir in eggs, combining completely. Cook over low heat until mixture thickens, about 20 minutes, stirring constantly so it doesn't stick or scorch. Cool. Pour into container and keep tightly covered for up to two weeks.
I doubled this recipe for my tea party of about 100 people.
I used bottled lemon juice (no orange juice), to make it extra tangy.