Line a plate or small tray with parchment paper. Scoop 17 teaspoon portions of peanut butter and place them on the parchment. Freeze 10–15 minutes.
In a mixing bowl, stir softened butter, brown sugar, and caster sugar until smooth.
Mix in the egg and vanilla paste until creamy and fully combined.
In a separate bowl, whisk flour, cocoa powder, salt, and baking soda.
Add dry ingredients to the wet mixture and stir just until combined. Fold in the chocolate chips.
Scoop a portion of dough, flatten it, place a chilled peanut butter portion in the center, and wrap dough around it. Roll into a smooth ball.
Place dough balls on a parchment-lined cookie sheet and chill 20–30 minutes.
Bake at 350°F (177°C) for 10–12 minutes, until edges are set and centers are still soft.
Cool on the cookie sheet 10 minutes, then transfer to a rack to cool completely.