Preheat the oven to 350 degrees. Line 2 cookie sheets with silicone baking mats or parchment paper.

Mix the butter and peanut butter in a large bowl with a hand mixer until smooth. Add both sugars and cream until fluffy.

Add the vanilla extract, egg, baking soda, and salt and mix until smooth. Then add the flour and mix just until a cookie dough forms.

Place the finely chopped peanuts in a small bowl. Scoop cookie dough balls (each about 1 tablespoon) and roll them between your palms. Roll the balls in the peanuts, pressing lightly to adhere, and then place them onto the prepared cookie sheets.

Bake for 9-11 minutes, rotating pans halfway through baking, until they just lose their glossy sheen and the bottoms are slightly golden. The cookies will stay in balls during baking.

Immediately after removing from the oven, carefully create a thumbprint in each cookie. Use the back of a 1/4 teaspoon, the handle of a wooden spoon, or your knuckle to create the indent.

Cool on the cookie sheets after removing and baking additional cookies.

While cookies are cooling, place the chocolate chips and heavy whipping cream in a microwave-safe bowl. Heat on high power for 1 minute, then whisk, heating for an additional 30 seconds, or as needed, to create a smooth chocolate ganache.

Spoon a bit of ganache into each thumbprint cavity. The ganache will harden as it cools, so wait to stack the cookies until after the ganache is completely cool.

Store in an airtight container for up to 3 days, or freeze for up to a month.