These salted caramel thumbprint cookies are so fun to make and even more fun to eat with a deeply flavored cookie crust and creamy caramel filling!
First, make the cookie dough. Line two sheet trays with silicone mats or parchment and set up a stand mixer with the paddle attachment. Whisk the flour, cocoa powder and salt in a medium mixing bowl and set it aside. Then cream the butter and two sugars together in the stand mixer until fluffy. Pour in the vanilla, followed by the two egg yolks. Finally, turn the speed to low and slowly add in the dry ingredients until you have a lovely dough. Use a 1.5 inch cookie scoop to scoop perfect mounds of the dough and round each scoop into a ball. Lay them out on the two sheet trays as you form them. Using that measurement, there should be 30 cookies total with 15 per sheet. They don't really expand so just leaving a little room is fine. Use your thumb to make a big indentation in the center of each ball of dough, then put the trays in the refrigerator to chill for an hour.
When the hour is almost up pre-heat the oven to 350. Bake the cookies for about 14-15 minutes, until they just start to crisp around the edges and bake through. Use your thumb to gently press down any rising in the indentations when they come out, then let them cool for a minute. Then transfer them to a cooling rack and start on the filling. Combine the caramel candies and heavy cream in a medium microwave safe bowl and microwave them on high for about a minute. Stir them together, then microwave it again for about another 30 seconds. When you stir them together after this, it should be really smooth and easy to work with. Use a heaping teaspoon to fill the indentation in each cookie, maybe more if your thumb is bigger than mine. Accounting for that, you may have more caramel filling than you need to use in other yummy ways. Once you fill all the cookies, sprinkle them generously with sea salt on top. Let them set completely in the refrigerator, then store them in airtight containers to enjoy or give away!