1 teaspoon vanilla extract

1 tablespoon chopped fresh rosemary

To make the curd: Place the lime and lemon juice, zest, yolks, egg, and sugar in a heat-proof mixing bowl. Whisk until combined. Fill a medium saucepan with a few inches of water and place the mixing bowl on top to create a double-boiler. Put over medium heat.

Cook the lemon-lime mixture until thickened, stirring with a heat-resistant rubber spatula. The mixture should thicken in 8 to 10 minutes. When finished, the mixture should coat the spatula.

Strain lemon-lime mixture into a heat-safe mixing bowl. Add the butter and whisk until smooth. Cover the lemon-lime curd with plastic wrap, pressing the plastic directly to the top of the curd to prevent a skin from forming. Allow to cool; the curd will continue to thicken as it cools.

To make the sable cookies: Sift together the flour and salt and set aside. Beat the butter with an electric mixer and a paddle attachment until smooth. Add the sugar and mix until creamed but not fluffy. Mix in the egg yolks and vanilla until combined. On low speed, mix in the dry ingredients and rosemary. Once the ingredients start to incorporate, turn mixer up to medium low and mix until just combined. Do not over mix.

Split dough in half, and turn the dough out onto two pieces of parchment paper. Form into two logs of dough, 1 1/2 to 2 inches in diameter. Wrap in the parchment, twisting the ends to seal. Chill dough in the refrigerator for at least three hours or in the freezer for 30 to 60 minutes.

Once dough is chilled, pre-heat oven to 350 F. Line a baking sheet with parchment or a Silpat mat. Remove one log of dough and unwrap it from parchment. Trim rough ends with a sharp paring knife, and then slice the dough into coins 1/4 to 1/2 inch thick. Place on baking sheet and bake until edges are browned, 12 to 15 minutes. Repeat with second half of dough.

Let sables cool before topping with lemon lime curd.

Note: Store lemon-lime curd in the refrigerator for up to a week.

(Tessa Huff is a writer for TheKitchn.com, a nationally known blog for people who love food and home cooking. Submit any comments or questions to kitchn@apartmenttherapy.com.)