After picking about 30 grapefruits from the tree this year, I could only eat and juice so many grapefruits, so I used the last ones to make curd.
Juice and grated rind of 8 grapefruits
2 cups white sugar
200 g (1/2 lb) butter
8 eggs, lightly whisked
Bring the grapefruit juice and rind to a simmer with the sugar until the sugar is dissolved. Cover, turn off the heat and let steep for 1 h. Strain out the rind using a fine sieve, return to the stove and bring to the boil, and remove from heat. Slowly add the hot mixture to the eggs while whisking. Once combined, return to the stove and place on low heat. Add cubes of butter, one at a time, while whisking, until combined. Cool for another few minutes and the curd will thicken (it will already begin thickening while adding the butter). Pour mixture into sterilised jars and seal.
To prepare sterilised jars, thoroughly wash jars and lids, and any funnels or spoons that you might use to transfer the cooked product. Place the jars and any heat resistant equipment on a baking tray lined with foil in the oven at 180 C (350 C) for at least 30 min. All other equipment sterilise using sterilising tablets dissolved in water according to instructions, followed by quick drying in a hot (100 C or 225 F) oven.