In a small saucepan, combine the yolks with the passion fruit, sugar and lemon juice. Cook over low heat, whisking, until the sugar dissolves. Add the butter and cook, whisking, until thickened, about 8 minutes. Immediately strain the curd into a bowl. Using a back of the spoon, press the juice through the sieve. Cover the bowl with plastic wrap and press the wrap onto the surface of the curd. Refrigerate until chilled.
Buttermilk Panna Cotta
In a large bowl, combine buttermilk, lemon juice and zest, whisk to combine. Set aside.
In a small bowl, fill it with 3 tablespoons cold water. Sprinkle the unflavored gelatin evenly over the water. Making sure that the powder does not get poured into only 1 spot. Set the bowl aside. It takes the gelatin about 3 to 5 minutes to bloom. The gelatin will be soft.
While the gelatin is blooming, combine heavy whipping cream and sugar in a medium sauce pot. Over medium heat, warm the cream and sugar to just below a simmer, stirring continuously to dissolve the sugar.
When the cream is just below a simmer, turn off heat and transfer the pot to a wire cooling rack. Gently whisk in the bloomed gelatin until incorporated.
Once the gelatin has been whisked into the cream, pour the hot cream into the buttermilk-lemon mixture and gently stir.
Carefully transfer the mixture and pour into individual cups, transferring the cups into the refrigerator until set. This takes about 3-4 hours, or works great to make the night before. Allow the panna cotta to cool down in the fridge for an hour before covering with plastic wrap.
When the buttermilk panna cotta is set, and you are ready to serve the dessert. Take 2 tablespoons of passion fruit curd and evenly spread over top of each glass. Top with freshly cut ugli fruit and serve.
Recipe by The Fruit Company® Blog at http://blog.thefruitcompany.com/passion-fruit-curd-panna-cotta-ugli-fruit/