Sprinkle gelatin over cold water in a small bowl, and let stand until softened, about 5 minutes.
Whisk together egg yolks, sugar, and salt in a large heatproof bowl. Gradually whisk in lemon juice. Place bowl over a saucepan of simmering water, and whisk constantly until mixture has thickened and registers 160 degrees on an instant-read thermometer. Whisk in gelatin mixture. Remove from heat, and whisk in butter, a few pieces at a time, until smooth. Let cool, stirring occasionally. Prepare an ice-water bath. Place bowl of yolk mixture over bath, and stir until slightly thickened, about 2 minutes.
Spread curd into crust; smooth top. Dollop creme fraiche on top. Using a wooden skewer or the tip of a knife, swirl creme fraiche into curd to create a marbleized effect. Refrigerate until firm, at least 2 hours (or up to overnight).
Like all the others, I followed the recipe strictly and used an instant read thermometer (and yes, it had been tested in boiling water for accuracy), and my curd did not set -- delicious lemon soup, but a disaster as a dessert. Other lemon curd recipes recommend cooking to a temp of 170 degrees. I'll try this again once because the flavor was fantastic, but today's try was epic fail.
A lovely tart! Made it for the first time yesterday and it turned out perfect. Not living in the US, I couldn't find granulated gelatin so I used sheets of gelatin (the more common version of gelatin in continental Europe) - if you have the same trouble use 2 sheets, seems to be just the right amount.
I am sure this recipe is wonderful when it turns out. I have made it twice with newly purchased ingredients, neither time the lemon 'curd' thickened. Quite upset, now my mom will not have a birthday 'cake'...
I've made this twice and it turned out great. Because it you make the crust and later the filling, it really isn't that time consuming or difficult.
Thank you You saved me a lot of time!!!
I found this recipe to be extremely difficult. I was careful to use my thermometer and use fresh ingredients but after a lot of work, it never set up. I had lemon soup. I would not recommend this recipe for the feint of heart.