Lemony Linzer Cookies

Ingredients

• 4 egg yolks
• 3/4 cup (150g) granulated sugar
• 1/2 cup fresh lemon juice
• zest of 2 lemons (1 tablespoon)
• 4 oz (112g) unsalted butter, cubed
• 3/4 pound unsalted butter, softened
• 1/2 cup granulated sugar
• 1/2 cup confectioner's sugar plus more for garnish
• 1/2 teaspoon salt
• 2 teaspoons pure vanilla extract
• 3 cups (500g) all-purpose flour

Instructions

1. 1

   Fill a saucepan with a few inches of...: Fill a saucepan with a few inches of water and bring it to a simmer. Place a heatproof bowl on top, making sure the bottom doesn't touch the water.

2. 2

   In the bowl, whisk together the egg yolks,...: In the bowl, whisk together the egg yolks, sugar, lemon juice, and lemon zest.

3. 3

   Cook over the simmering water, whisking constantly, until...: Cook over the simmering water, whisking constantly, until the mixture thickens to a pudding-like consistency and coats the back of a spoon (about 8–10 minutes). Be patient and don’t raise the heat—slow and steady prevents curdling.

4. 4

   Remove the bowl from the heat and immediately...: Remove the bowl from the heat and immediately whisk in the butter cubes until smooth.

5. 5

   Cover with plastic wrap pressed directly on the...: Cover with plastic wrap pressed directly on the surface and refrigerate until thickened (at least 2 hours or overnight).

6. 6

   Preheat the oven to 350°F (180°C) and line...: Preheat the oven to 350°F (180°C) and line 2 baking sheets with parchment paper.

7. 7

   In the bowl of a stand mixer (or...: In the bowl of a stand mixer (or using hand beaters), beat the butter, granulated sugar, and confectioner's sugar together until light and fluffy—about 3–4 minutes.

8. 8

   Add the salt and vanilla extract and mix...: Add the salt and vanilla extract and mix to combine.

9. 9

   Gradually add the flour and mix on low...: Gradually add the flour and mix on low speed until a soft dough forms.

10. 10

    Roll out the dough on a lightly floured...: Roll out the dough on a lightly floured surface to about 1/4-inch (6 mm) thickness.

11. 11

    Cut out cookie rounds with a fluted cutter....: Cut out cookie rounds with a fluted cutter. For half of them, cut out a small circle or heart from the center to create the “window.”

12. 12

    Transfer cookies to prepared sheets and bake for...: Transfer cookies to prepared sheets and bake for 15-20 minutes, or until the edges are just turning golden.

13. 13

    Let cool completely on the baking sheets.

14. 14

    Spread about 1 teaspoon of lemon curd onto...: Spread about 1 teaspoon of lemon curd onto the flat side of each full cookie round.

15. 15

    Dust the cut-out cookies (the tops) with confectioner's...: Dust the cut-out cookies (the tops) with confectioner's sugar before sandwiching them on top.

16. 16

    Gently press together and let sit for 30...: Gently press together and let sit for 30 minutes to set.