• Preheat oven to 350° F and line 2 pans with silicone mats or parchment paper.

To make the cookies:

• In a medium bowl, whisk together the flour, baking soda and salt. Set aside.
  4 cups flour, 1 tsp baking soda, ¼ tsp salt
• In a stand mixer, beat butter until soft; add dulce de leche and both sugars and beat until fluffy.
  2 sticks unsalted butter, 7 oz dulce de leche, 1 cup dark brown sugar, ½ cup caramel sugar
• Add eggs one at a time beating for 1 minute after each addition.
  2 large eggs
• Reduce mixer to low and add the dry ingredients mixing only until they disappear in the batter.
• Scoop the batter onto the baking sheets leaving 2 inches between cookies.
• Bake for 10 – 12 minutes until honey brown with light sugar crust. Let cool on pan for a couple minutes before moving to a rack to cool completely.

To make the filling:

• Place the dulce de leche, semisweet chocolate and heavy cream in a microwave safe bowl. Heat in 30 second bursts, stirring well in between until all of the chocolate is melted and the mixture is smooth and glossy.
  6 ½ oz dulce de leche, 1 cup bittersweet chocolate, ¼ cup heavy cream

Assembling the sandwich cookies:

• Spread the flat bottoms of half the cookies with the dulce de leche ganache filling and sandwich with the flat sides of the remaining cookies.