Chilean Alfajores

Step 1
Place the entire, unopened can of condensed milk in a large saucepan. Fill the saucepan with water and bring to a boil. Lower heat to a simmer and cook until milk inside has caramelized, about 2 hours.

Step 2
Remove from the heat and set aside to cool while you make the cookies.

Step 3
Preheat the oven to 325 degrees F (165 degrees C).

Step 4
Beat butter and sugar together in a bowl with an electric mixer until creamy. Mix in egg, then mix in flour until well combined.

Step 5
Drop batter by small teaspoonfuls onto an ungreased cookie sheet. Dip your finger into flour, and pat each cookie into a very thin, little circle (about the size of a quarter).

Step 6
Bake in the preheated oven until just starting to brown around the edges and no longer doughy in the centers, 10 to 12 minutes. Cool on the cookie sheet for 1 minute before removing to a wire rack to cool, 8 to 10 minutes more.

Step 7
Sandwich cooled cookies together with the caramelized condensed milk.