Preheat oven to 170 degrees Celsius (fan forced).

In a bowl, combine the flour, baking soda, baking powder and salt. Set aside.

In a large mixing bowl, beat the butter and peanut butter mixture together until it turns fluffy. Add in light brown sugar and continue to beat until it reaches a smooth consistency.

Add in the egg and mix in well. Add in the milk and vanilla extract.

Add in the flour mixture (from the first bowl) and beat thoroughly. Mix in the crushed peanuts and chocolate chips and stir well.

On a clean plate, sprinkle some caster sugar around. To form the cookies, start by scooping out a teaspoon full of cookie dough and rolling it in the palm of your hands to form a ball. Place the cookie ball onto the sugar coated plate. Keep forming the cookie balls until the dough is all used up.

Place each cookie ball onto ungreased cookie sheets or a Silpat (if you have one), leaving several inches between each cookie for expansion. I only have one Silpat mat, so I did about 4 rounds of baking with this.

Using a fork, lightly indent the cookies with a criss-cross pattern. To smooth it out, I lightly patted each cookie after the patterns were made with a flat spatula, keeping in mind to not overly flatten cookies.

Bake cookies for 10 to 12 minutes. Do not overbake. Cookies may appear to be underdone, but they are not. They will harden up when they cool.

You should have roughly 60-70 cookies when you finish (depending on the size of the spoon you used to form the cookie balls).

Leave the cookies to cool on the sheets for 1 minute, then remove to a rack to cool completely.