Make the Cookies

1. In the bowl of a stand mixer fitted with the paddle attachment, cream together the powdered sugar (3/4 cup or 115 grams), kosher salt (1/2 teaspoon), and unsalted butter (16 Tablespoons or 226 grams, cut into tablespoon-sized slices) on medium-high speed. Scrape down the bowl and paddle regularly and don’t move onto the next step until it is evenly lightened in color and fluffy.

   Tip: this step goes faster if you use room-temperature butter.

   
   
   

2. Scrape down the bowl with a rubber spatula, then add the egg (1 – large) and vanilla extract (1/2 teaspoon) and beat on medium speed until it is uniform in texture and there are no shiny streaks. It should look like the consistency of a thick cake batter. Finish this step by mixing on medium-high speed for 15 seconds.

   Tip: There will be a stage where it looks like cottage cheese – this is normal! Scrape down the bowl and keep going. It will come together, I promise.

   
   
   

3. Add the unbleached all-purpose flour (2 cups spooned and leveled, see Note*, or 276 grams) and pulse until the flour is integrated (about 10 pulses), then combine on medium-low until there are no flour patches in the dough or hiding at the bottom of the bowl.
   
4. Using a small cookie scoop, portion out the dough, then roll each dough portion into a smooth ball between your palms
   
   
5. Use your thumb or the back of a rounded teaspoon to press a well into the middle of each dough ball, then place on a plate, cover, and chill in the fridge for 1-2 hours.

   Tip: if using a rounded teaspoon, wipe off the back with a clean towel every four cookies or so to help the process go smoothly.
   
   

6. Preheat your oven to 375 F.
7. Bake for 12-15 minutes on a rimmed baking tray until no longer shiny, then remove from the oven and allow to cool on the tray.

   Tip: The cookies are done when they’ve spread slightly, they no longer look wet or have a shine to them, and the edges are just starting to turn golden.

8. Allow the cookies to cool completely before filling the wells with chocolate ganache.

Make the Ganache & Fill the Cookies

1. Add the semi-sweet chocolate chips (3/4 cup) and kosher salt (1/4 teaspoon) to a heat-proof bowl and set aside until the cream has heated.
   
2. In a small saucepan over medium heat, warm the heavy whipping cream (1/2 cup) until it begins to steam but doesn’t quite reach a simmer, swirling occasionally.

   Tip: do not step away from the stove as the cream should reach temperature rather quickly, and dairy can quickly get out of control if left unattended on the stove.

3. Once the cream is steaming, remove from the heat and pour evenly over the chocolate chips. Give the bowl a swirl so that all of the chips are covered, then let rest untouched for 5 minutes.
   
4. With a flexible spatula, gently stir together the milk, kosher salt, and semi-sweet chocolate chips until smooth, and all of the chocolate is melted.

   Tip: if your ganache breaks (starts to look grainy or oily), add a teaspoon of hot water and vigorously whisk into your ganache until it starts to come back together. If it doesn’t start to re-emulsify, add another teaspoon of hot water and repeat.
   
   
   

5. While still warm, spoon a 1/2 teaspoon of chocolate ganache into the well of each cooled cookie.
   
6. For best results, allow the ganache-topped cookies to set at room temperature for about two hours or in the fridge for an hour.

Store covered at room temperature for up to three days, or about a week if covered in the fridge.

Check out the blog post for this recipe if you’re looking for ideas to use any leftover ganache!