Heat heavy cream in a small saucepan until it just begins to bubble. Stir constantly as it will heat quickly and could easily burn! Pour the hot cream over the chocolate and stir until it has melted and is fully incorporated.Cover the bowl with cling wrap and store it in the freezer until it is solid (roughly 30 mins). Leave in the freezer until you’re ready to make the cookies.
Make the double chocolate cookies
In the bowl of a stand mixer (or large mixing bowl with a hand mixer) beat the butter, sugar, and brown sugar until light and fluffy.
Stir down the sides of the bowl and then add in the vanilla extract and the egg. Mix until just combined.
Stir down the sides of the bowl again and add in the dry ingredients. Mix until combined. Stir in the chocolate chips.
Shape the cookies
Preheat the oven to 350F and prepare a baking sheet.
Use a 2-tablespoon cookie scoop to scoop out a ball of dough. In your hand, flatten the ball and place ½ a teaspoon of chilled ganache in the center. Fold the dough over the ganache and roll it into a ball. Roll the dough ball in the sugar mixture then place it on a prepared baking sheet 2 inches apart.
Bake at 350F for 13-15 minutes (14 is my sweet spot in my oven!). Put the ganache back in the freezer between batches. Allow them to cool on the baking sheet for 5 minutes before moving to a cooling rack.
Notes
Weigh your ingredients! I can't recommend this enough. Kitchen scales are easy to find, affordable, and beneficial to your baking journey. It is the best way to make sure your recipes turn out as accurate as possible. See my "equipment" section above for links to scales I recommend.
Tip: You will know that the cookies are done when they are no longer shiny on top! Make sure you let them cool on the pan for a few minutes before moving them to the cooling rack so that the bottom can set to support the gooey ganache center!
Storage: Store at room temperature for up to 7 days. You can freeze these double chocolate-filled cookies for up to 6 months; just be sure to thaw them in the fridge to prevent them from getting soggy from condensation.