The BEST Linzer cookies (Spitzbuben)

Mix together butter, sugar, lemon zest, and your egg yolk paste until incorporated. Add in the flour and milk and knead until you have a cohesive, smooth dough.

Cover the dough and transfer to the fridge to chill for 60 minutes. In the meantime, preheat oven to 390° Fahrenheit (200° Celsius).

On a surface dusted in flour, roll out the dough to 1/10 inch (3 mm) thickness, and cut out your favorite shapes, cutting out the middle for half of them, so you see the jam through it after assembly. Note: You can use a special cookie cutter for these, or you can create your own Spitzbuben by creating any kinds of peek-a-boo holes in the top cookie. If they are larger sized cookie shapes like mine, you'll end up with less than 40 cookies.

Transfer cookies to baking sheets covered in parchment paper or fitted with baking mats and bake for 8 to 10 minutes on the middle rack until just starting to turn golden around the edges. Note about baking: My last batch could fit on just one baking sheet instead of two, and the cookies baked much faster. I would also recommend baking the top pieces with cut-outs separately from the bottom pieces as they tend to bake just a minute or so faster.

After baking, carefully pull the baking sheet or parchment paper onto a cooling rack, allowing the cookies to harden and cool down faster. Dust top cookie with powdered sugar. Using spoons, put about 1/2 teaspoon of jam on each bottom cookie (you can warm it up in the microwave for a few seconds to help it spread out better), then assemble the cookies by placing the sugar-dusted top cookie on the jam-covered bottom cookie. These keep well in a cookie jar for up to 2 months (but no way you'll have any left after the first week).