• Preheat oven to 350 degrees F.
• In a large mixing bowl cream together butter and sugar together until light and fluffy.
• Add eggs one at a time, mixing until incorporated.
• Add vanilla extract and mix until combined.
• In a separate bowl, whisk together cocoa, salt, baking soda, baking powder and all-purpose flour.
• Slowly add dry ingredients to wet ingredients, mixing until just combined.
• Use a 1 inch cookie scoop, and roll dough into 1 inch balls.
• Place on greased or lined baking sheet.
• Using the back of a rounded measuring spoon, or your thumb, press a well into center of each cookie.
• Bake at 350 degrees for 11-12 minutes, until edges are dry, but center is soft.
• If the "thumbprint" is no longer there, use the same measuring spoon to re-indent the center of the cookie.
• Let cool on baking sheet for 2-5 minutes.
• Remove from baking sheet and cook on a wire cooling rack.

Center

• While cookies cool, use a small saucepan over medium heat, to melt together the white chocolate chips and sweetened condensed milk.
• Once melted together, remove from heat, and stir in mint extract.
• Spoon center filling into the center of each cookie.
• In a small bowl, melt the chocolate chips in the microwave by heating in 20 second increments, and stirring between each.
• Once melted (about 40-60 seconds), drizzle melted chocolate over cookies.
• Let the chocolate set and the fudge like center set, and serve or store in an air tight container.