Chaud Froid De Pamplemousse au Romarin

To make the curd, in a bowl, stir together the sugar and cornstarch. Whisk in the lemon juice, egg yolk, and whole egg, mixing well. (Reserve the egg white for later.) Strain through a sieve into a bowl. Stir in the lemon zest and butter.

Pour the mixture into a thick-bottomed saucepan and place over medium heat. Heat, stirring constantly, including into the corners of the pot—until the mixture reaches 185°F (84°C). You will notice it starting to bubble along the sides of the pan. When you see the bubbles, immediately transfer it to a bowl and refrigerate it.

Rinse the saucepan so you can use it for the syrup. Add the sugar and water, stir once, and bring to a boil over medium heat. Remove from the heat, add the rosemary, and allow to infuse for 5 minutes. Strain the syrup through a sieve and set aside.