With a hand mixer or a stand mixer fitted with the paddle attachment, beat together the butter and sugar until the mixture is light and fluffy (2-3 min.)
Beat in the egg and vanilla until well combined.
Add in the flour, cocoa powder, baking powder, and salt. Beat the mixture together just until no flour streaks remain.
Cover the dough and leave it in the fridge to chill for at least 30 minutes, or for up to 2 days.**
In the meantime, make the french silk pudding.
French Silk Pie Pudding
In a small bowl, whisk together the instant pudding, heavy cream and milk until combined and no clumps remain. Cover the pudding and let it sit in the fridge until you're ready to assemble the cookies.
Once the cookies have chilled, preheat the oven to 350°F / 175°C. Line a cookie sheet with parchment paper or with a silicone baking mat.
Use a 3 tbsp. cookie scoop to dish out the cookies onto the prepared cookie sheet. Evenly space the cookies apart to allow room for spreading. Bake for 10-12 minutes, until the sides of the cookies have set and the middles look just slightly undercooked.
Use the bottom of a pinch bowl or shot glass (~2-3") to carefully indent the center of each cookie while they are still warm, within 5 minutes of them coming out of the oven. The outer ring of the cookies may break apart a little, but you can mold it back together while it's still warm.
Whipped Cream
Add the heavy cream, sugar, and vanilla to a small mixing bowl. Whisk together (or beat with a stand mixer) until you have formed soft peaks in the cream.
Once the cookies have come to room temperature, place 2 tbsp. of chocolate pudding in the center of each cookie. Use a spoon to slightly spread it around to fill the indentation.
Top each cookie with a dollop of whipped cream and chocolate curls if desired. Serve and enjoy!
Notes
Affiliate links: Kitchen Scale (my favorite) | Kitchen scale (great starter option) | | Oven Thermometer | Cookie Scoops | Cookie Sheet Pan | Milk Pan*A standard small packet of Jell-O instant chocolate pudding is 3.9 oz / 110g. You'll only need half of that packet for one batch of these cookies. You can choose to make the whole packet and keep extra pudding in the fridge, or just use half of the packet with 1 cup of heavy cream/milk and save the powder for another time!**If you're chilling them overnight, you'll want to take the dough out for at least 30 minutes before baking until the dough is warm enough to be scoopable again.Keep extra cookies stored in an airtight container in the fridge. While these cookies are super delicious cold, if desired, you can take them out 30 minutes before eating them to come to room temperature.