Here's a recipe few have even heard of. It's great on Pound Cake, and after using it, I'd bet you can find other uses, too! I've taken the liberty to remove the metric equivalents to avoid confusion. I also altered the canning instructions to reflect current U.S. canning recommendations.
5 oz. Sugar
3 Egg yolks, well beaten
The Grated Rind and juice of 3 Tangerines
4 oz. Butter
Recipe
Prepare the jars (see notes below). Place the sugar, rind, juice and butter into the inner pan of a double boiler and cook over a saucepan containing hot water. Stir from time to time, until the margarine and sugar have melted. Add the eggs and continue cooking until the mixture is thick enough to coat the back of a wooden spoon, about 20 minutes. Pour into jars, cover and seal (see notes below).
Jars - Use jars which are free from cracks, chips or flaws – the best sizes to use are half pint (8 oz.) or pint (16 oz.) jars. Prepare the jars and lids by washing well in warm soapy water and rinsing thoroughly. Dry the jars in a cool oven (275F). Fill while still warm to prevent the jars from cracking when the hot filling is added.
Filling the jars – Fill to the top leaving 1/4 inch head space, then wipe the rims of the jar with a damp cloth. Immediately cover with two piece lids while still hot and allow to cool. Refrigerate. For long term storage, process for 10 minutes in a boiling water canner. Store in a cool dark place.