Karen Gottlieb 

For the shortbread:  
3 cups all-purpose flour  
1 1/2 cups (3 sticks) unsalted butter  
1/2 cup granulated sugar  
1/3 cup confectioners' sugar, plus additional for sprinkling  
1 tablespoon chopped fresh rosemary  
1 teaspoon finely grated lemon zest

For the lemon curd:  
6 large eggs, lightly beaten  
1 1/2 cups granulated sugar  
2/3 cup freshly squeezed lemon juice (3 to 4 lemons)  
1/4 cup all-purpose flour  
1 tablespoon finely grated lemon zest  
1 pinch kosher salt

1. Preheat the oven to 325° F and lightly grease a 9- by 13-inch baking pan.

2. To make the shortbread base, combine the flour, butter, granulated sugar, confectioners' sugar,rosemary, and salt in a food processor. Pulse until crumbly dough forms. Press the dough into the prepared pan and bake until the shortbread is golden around the edges, about 40 minutes.

3. While the shortbread is baking, prepare the lemon curd. In a large bowl, whisk together the eggs,sugar, lemon juice, four, lemon zest, and salt.

4. When the shortbread is ready, take it out of the oven and increase the temperature to 350° F. Carefully pour the lemon curd onto the shortbread base and return the pan to the oven. Bake until the topping is just set, about 20 minutes more. Allow to cool to room temperature before cutting into 2-inch squares. Cover and refrigerate the bars up to 3 days. Sprinkle with confectioners' sugar before serving.

Time: 1 hour 15 mins.   Yield: 24 squares