In a large bowl, cream together the ¾ cup of chunky peanut butter, ½ cup of room temperature butter, and 1 cup of packed brown sugar. Use an electric mixer and beat the mixture until it is well combined and creamy.

Crack the egg into the mixture, add the 1 ½ teaspoons of vanilla extract, and mix well until these ingredients are fully incorporated.

In a separate bowl, combine the 1 ¼ cups of all-purpose flour, ½ teaspoon of baking powder, and ½ teaspoon of baking soda. Stir these together to ensure they are evenly mixed.

Gradually add the dry ingredient mixture to the peanut butter mixture, mixing until just combined. Be careful not to overmix as this can make the cookies tough.

Chill the dough in the refrigerator for about 1 hour. This will make it easier to handle and shape into balls.

Preheat your oven to 375°F (190°C), and line a baking sheet with parchment paper.

Use a large ice cream scoop or your hands to form the dough into balls. Place these onto the prepared baking sheet, spacing them about 2 inches apart to allow for spreading.

Using the back of a fork, gently press down on each ball of dough in a crisscross pattern to flatten them slightly.

Bake in the preheated oven for about 10 minutes, or until the edges of the cookies are lightly golden.

Allow the cookies to cool on the baking sheet for about 5 minutes, then transfer them to a wire rack to cool completely.

Once the cookies are completely cool, spread a dollop of Nutella on top of each one.