In a large bowl, cream together the butter with the granulated and brown sugars.
Add the eggs, baking soda, cocoa powder and vanilla extract to the bowl and beat until well combined.
Add the flour to the bowl and mix until just combined- don't overmix! Refrigerate the dough for about 20 minutes.
Scoop the dough 2 Tbsp at a time and press into circles in your palm about ½" thick. Scoop 1 tsp of hot fudge from the jar and place it in the center of the dough circle. Close the dough around the fudge and roll in your hands until round. Roll the dough in granulated sugar and place 2" apart on a baking sheet covered in parchment paper.
Place the baking sheet back in the fridge for about 20 minutes while you preheat the oven to 350°.
Bake for 9 minutes and remove cookies from oven. Allow the cookies to cool on the sheet for at least 10 minutes before removing to a baking rack to finish cooling.
