Alfajores Cookies

For the dulce de leche:
Put all ingredients in a pot and turn on medium heat. Keep an eye on it, as the milk may get too hot and boil over. Cook over heat for about 2 hours. The milk will reduce and caramelize. Once mixture looks like a rich caramel color, remove from heat and pour into a heat proof bowl.
 
Very important: Let it chill for 2 hours before use! The dulce de leche will firm up as it cools.
 
For the cookies:
Preheat oven to 350ºF (176ºC).
 
Start by putting the room temperature butter into a mixer fitted with a paddle attachment. Turn to medium. Slowly add sugar, and cream butter and sugar together.
 
Add egg yolks and continue to cream together, scraping down sides of the bowl. Add Amaretto (or brandy, whichever you choose).
 
Sift all the dry ingredients together (except powdered sugar, which will be used for dusting finished cookies). Add dry ingredients in three batches, scraping down sides of bowl after every addition. After dry ingredients have been incorporated, dough should come together. Take dough out, wrap in plastic, and let chill for 30 minutes.
 
After dough has rested, roll out on a flat surface lightly dusted with flour. Roll dough to about 1/8 inch. Punch out small circles (I used a fluted 1 1/2 inch cookie cutter) and place on a cookie sheet fitted with some parchment paper. Place cookies about 1 inch apart.
 
Chill cookies again before baking. The cookies will come out better if dough is cold.
 
Bake cookies for 6 minutes. Rotate the pan and bake another 6 minutes. You’re looking for golden brown edges.
 
Cool completely before assembling cookies.
 
To assemble alfajor cookies, transfer dulce de leche into a piping bag. Line up two cookies side by side. Pipe about 1 teaspoon dulce de leche onto every other cookie. Sandwich together. To finish, sift powdered sugar over top of sandwiched cookies.