Start by melting butter in a microwave-safe bowl until it’s completely liquid but not super hot – about 45 seconds, stirring halfway through. If it’s too hot, your eggs will scramble when you add them later.

Pour the melted butter into a large mixing bowl and add the granulated sugar. Whisk them together until well combined – the mixture will look like wet sand.

Add the eggs one at a time, whisking well after each addition. You want the mixture to become smooth and slightly thicker with each egg. Once all four eggs are in, add the vanilla and whisk until the mixture looks glossy – about 30 seconds.

In a separate bowl, whisk together cocoa powder, flour, salt, and baking powder. This prevents any cocoa powder lumps in your final cookies.

Gradually add the dry ingredients to wet mixture, stirring with a rubber spatula. Stop mixing as soon as you don’t see any more dry flour – overmixing will make your cookies tough. The dough will be quite soft, almost like a thick cake batter.

Cover the bowl with plastic wrap and refrigerate for at least 2 hours. This is crucial – the dough needs to firm up so you can roll it later.

While the dough chills, make your filling. Mix the peanut butter, powdered sugar, and milk in a bowl until smooth. It should hold its shape when rolled but still be creamy – if it’s too stiff, add milk a few drops at a time.

Roll the peanut butter mixture into 24 small balls (about 2 teaspoons each) and place them on a parchment-lined plate. Pop these in the freezer for at least 30 minutes – this makes them much easier to wrap with cookie dough.

When ready to bake, preheat your oven to 350°F and line baking sheets with parchment paper.

Scoop about 2 tablespoons of chilled cookie dough and flatten it in your palm. Place a frozen peanut butter ball in the center and wrap the dough around it, sealing completely. Roll into a ball and place on your prepared baking sheet. Leave about 2 inches between cookies – they will spread.

Bake for 12-14 minutes, rotating the pan halfway through. The cookies are done when the edges are set but the centers still look slightly soft – they’ll continue cooking as they cool. You should see small cracks on the surface.

Let them cool on the baking sheet for 5 minutes – they’re very soft right out of the oven. Then transfer to a wire rack to cool completely.