You can make a curd using various fruits and berries, as long as you remember to still use 1/3-1/4 of the lemon juice in the basic lemon curd recipe. In the ‘sort of’ Meyer lemon curd I used a combination of lemon and orange juice, and equal amounts of zest, for a tasty substitute for REAL Meyer lemon juice using this principle.
I used 2 tbsp of lemon juice and enough blood orange juice to make up 1/2 cup juice in total when making this blood orange curd. And 2 tbsp of blood orange zest. It tasted delicious, but, unfortunately, the resulting curd lost the vibrant red colour of the juice when mixed with the yolks and cooked.