The recipe is unique in that you actually bake the jam in the cookie, instead of waiting until they've been baked to add in the filling. I liked that, because it makes them a bit more cohesive and as such, easier to transport. If you like citrus as much as my mother, you will love these cookies. And even if you don't really like citrus (like my brother), you'll probably still like these. (He did.)
Makes about 40 cookies.
1/2 cup jam (I used raspberry and apricot preserves)
2-1/4 cups flour
1 tsp baking powder
1/4 tsp kosher salt
2 sticks butter, at room temperature
2/3 cup sugar
2 large egg yolks
1 tbsp lemon zest (about 1 lemon)
1 tbsp fresh lemon juice
1 tsp vanilla extract
Preheat the oven to 350 degrees Fahrenheit. Line 2 large baking sheets with parchment paper.
In a medium bowl, whisk flour, baking powder, and salt together.
In a large bowl, beat butter and sugar at medium speed until creamy. Beat in the egg yolks, lemon zest, lemon juice, and vanilla until combined. Add in the flour, half at a time, and beat at low speed until a ball has formed. Use your hands if necessary.
Form dough into 1-inch balls. Place on prepared baking sheet one inch apart. Lightly flour your thumb and press the center of each cookie gently. I recommend doing this after each row of cookies has been added, because the dough begins to harden and crack a bit if you wait until all the balls have been formed.
Fill each indentation with 1/2 tsp of jam. Bake 18 to 20 minutes, or until edges are golden brown.