Mise en Place the Lemon Curd Filling

• Soften silver leaf gelatin in cold water for about 10 minutes.

• Alternately, sprinkle the powdered gelatine over 1 tablespoon cold water. Let it bloom for about 10 minutes.

• Crack the eggs and egg yolk into a small bowl. Keep the eggs and sugar separate until your ready to make the lemon curd. The minute you combine the eggs and sugar, the egg will begin to coagulate and reduce its thickening properties. Read more about handling eggs. Visit The Finer Cookie’s post on How to Separate Eggs.
• Measure the sugar into a small saucepan and set aside.
• First zest the lemons with a microplaner, then juice them. Set aside the zest and juice separately. For a complete discussion on zesting citrus, see The Finer Cookie’s post How to Zest Citrus.

• Measure the butter and set aside.
• Set out your candy thermometer.

Make the Lemon Curd

• Whisk together the egg and sugar until completely homogenous.
• Slowly pour the lemon juice into the sugar and egg mixture.

Set it over medium heat, stirring constantly with a flat edge spatula. The idea is to keep all the ingredients suspended and keep them from settling on the bottom of the pan. This will cause your curd to have lumps.

• Stir until the mixture thickens and reaches 170F to 175F. The egg will be thoroughly cooked through at this temperature. In the absence of a thermometer, the curd will become very thick and will leave a path on the spatula.
• Drop in the sheet of softened gelatine. Alternately, scoop in the bloomed powdered gelatine. Stir until completely melted.

• Add the butter and melt slowly.

• Strain the lemon curd through a fine mesh strainer.

• Add the lemon zest and stir.

• Let cool to room temperature. Ideally let it sit in the fridge for about an hour. This will help you get a better consistency.

Mise en Place the Cookie Dough

• Weigh or measure butter and sugar into a mixing bowl of either a stand mixer or hand held mixer.
• Crack the egg into a small bowl and add the vanilla; Measure and combine the flour, baking powder, and salt into a medium bowl and set aside.
• Line two baking sheets with parchment.
• Lay a sheet of plastic wrap or a sheet of parchment on a clean section of counter top.
• Gather the rolling pin, a small offset spatula, and (1) egg shaped cookie cutter, round piping tip for the yolk hole.

Assemble the Cookie Dough

• Cream the butter and sugar until very light and fluffy. Click here to read The Finer Cookie’s post on how to cream butter and sugar.
• Add the egg and vanilla and beat until well incorporated and very smooth.
• Add the dry ingredients and mix just until incorporated.

• Gather the dough and divide in half and wrap one half in plastic and refrigerate for at least one hour or overnight.

Roll and Cut the Cookies

• Preheat the oven to 350F.
• Roll the dough to ?…? inch thickness. The dough will be soft but hardly sticky. Dust with the smallest amount of flour, just to relieve the stickiness if necessary.
• Cut an equal number of oval cookies. On half the cut cookies, use the pastry tip to cut the egg yolks just off center. You want the cookie sandwiches to look like an egg and egg yolk.

• Place the cut cookies on the prepared tray.

Bake the Cookies at 350F for 7-10 minutes

• Bake the cookies in a 350F oven for about 7-10 minutes. If you’re baking two trays at a time, watch the top tray carefully and rotate them to avoid browning. Cookies that are too brown won’t be as attractive.

Fill the Cookies

• Separate the baked bottom cookies from the top cookies.
• Fit a small piping bag with a 1/4 inch pastry tip.
• Fill the bag half way with lemon curd filing.
• Pipe lemon curd around the perimeter of the cookie bottom.
• Gently lay the top cookie over the filling.
• Pipe lemon curd into the hole of the top cookie.

• Best served the same day. Over the course of a week, the filling will soften the cookie.