Preheat the oven to 350 °F (175 °C) and line a cookie sheet with a piece of parchment paper.

Place the chopped pecans in a small bowl.

In a medium mixing bowl, stir together the flour, cocoa powder and salt. Set aside.

In a large mixing bowl with a stand mixer or electric hand mixer, beat together the butter and sugar at medium speed until well combined.

Add the eggs and vanilla. It'll look slightly curdled and odd at this point.

Gradually beat in the flour mixture.

The dough will be quite thick. Roll into thirty-two 27-gram balls.

Roll in the chopped pecans.

Place on the prepared cookie sheet, about 2” (5 cm) apart, and make an indentation into the top of every cookie with the back of a 1-teaspoon measuring spoon.

Bake for 10-13 minutes or until the pecans have browned and the top of the middle of the cookies appears dry and not wet. Wash the teaspoon and use it again to refresh the indentation.

Let cool completely. While they're cooling, prepare the caramel.

Place the sugar, salt, cream of tartar, and water in a deep, heavy-bottomed saucepan that holds at least 1 1/2 quarts (the syrup will bubble up as it cooks). Stir briefly to combine, then set the pan over medium-high heat. From this point on, swirl the pan instead of stirring to help prevent crystals from forming.

When the mixture comes to a boil, reduce the heat to medium and watch it carefully. No walking away! The syrup will start turning golden at the edges. Gently swirl the pan without lifting it off the heat to even out the color.

As the syrup darkens to light amber, remove the pan from the heat as soon as you notice darker streaks. Avoid letting the sugar syrup become too dark, as it will continue to cook slightly after being removed from the heat. Darker syrup has a richer flavor, but letting it go past medium amber can result in bitter or smoky notes.

Immediately after removing the caramel from the heat, stir in the butter, one tablespoon at a time. Gradually add the heavy cream, stirring until fully incorporated. Return the pan to the heat and continue cooking until the mixture reaches 235 °F (113 °C). Remove from the heat again, stir in the vanilla, and mix until smooth.

Let the caramel cool in the pan on a cooling rack for 30–40 minutes. If you want it to cool faster, transfer it to a wide, shallow, heatproof container. The caramel should still be pourable but not too runny.

This caramel can be made up to 3 days in advance and stored in the refrigerator. It will firm up in the fridge, so reheat gently to make it pourable again.

In a small microwave-safe bowl, melt the caramels and milk, cream or half-and-half together in the microwave for about 30 seconds. Stir until smooth and fully combined.

Once the caramel has cooled, spoon caramel into the cookies (about 1 teaspoon if using caramel option 1 or 3/4 teaspoon if using option 2). If your caramel is still kind of liquidy, then refrigerate the cookies until it’s firmed up (about 1 hour in the fridge or 15 minutes in the freezer). You want it to be able to hold up the chocolate.

Refrigerate in an airtight container for up to 3 days. They can also be frozen for up to 3 months.