Preheat oven to 180° C (350° F).
In a medium bowl, whisk flour, baking soda, and cinnamon together.
In a double boiler, melt chocolate chips.
In a medium metal bowl, beat softened butter, sugar, melted chocolate and milk together. Beat in eggs and vanilla. Using a wooden spoon, gradually stir in flour mixture until well combined. Fold in melted chocolate chips.
Roll dough into 1 inch (2.5 cm) balls, press the middle down with your thumb, and place 1 inch (2.5 cm) apart on greased cookie sheet.
Bake for 8 to 9 minutes. Let cool on a wire rack.