In a bowl, mix the butter and condensed milk for few minutes.
Add almond flour and mix it.
Add the flour and cornstarch and mix everything together. The dough should be sticky.
Cover with plastic wrap and refrigerate for about 1 hour.
Form small balls with the dough.
Place the balls of dough on a baking sheet lined with parchment paper.
Bake at 350℉ preheated oven for 15 minutes
Let cool for about 10 minutes.
Brush the base of each 2 cookies with condensed milk.
Assemble each 2 cookies together.
Brush the assembled cookies around with condensed milk and roll in almond flour or chocolate sprinkles.
Enjoy.