1. Mix butter and sugar in pot over medium heat. Beat continuously with wire whisk
until butter and sugar are well combined.
2. At this moment, add the zest of the grated lemon in order to express as much flavor as possible.
4. It is not supposed to darken in color than butter.
Remove from the heat, add
eggs beating them in thoroughly.
Cook this over medium heat 2 or 3 min while whisking rapidly to avoid scrambling eggs.
6. This will provide a light yellow liquid, thinner than before.
7 Add yogurt, lemon juice and mix well; finally mix in vanilla.
8. Pour it into a non-reactive container (plastic bowl) to cool for 10 mn or until just warm, whisking occasionally.
9. It is better used the next day or after a 6 hour refrigeration
10. Divide the mix into glass baking pans and bake at 250F for
as long as it is to the mix to set
11. Let cool outside for an hour or two ,then in kitchenaid mixer, beat the curd until completely
12. Divide in plastic containers, sealed and keep
refrigerated until needed.