Preheat to oven to 180ºC.

In a medium bowl using an electric hand whisk cream the butter and the sugars until light and fluffy.

Add in the egg and peanut butter and whisk again until completely incorporated. Pour the flour and bicarb of soda to the bowl and use a wooden spoon or spatula to stir in the flour to make the dough.

Use a cookie scoop or a tablespoon to measure out 3 tablespoons of dough and form into small golf ball size cookies. Leave 2 inches of space between each cookie. Gently flatten with your fingers, then using a fork imprint the dough with a criss cross pattern.

Bake in the preheated oven for about 10 minutes and remove when the cookies are light golden and just set in the middle. Let cool on the baking tray for about 5 minutes before removing them to cool on a cooling rack.

Melt the chocolate in the microwave or in a bowl over a pan of simmering water. Once the chocolate is melted, using a spoon, drizzle over the cookies and sprinkle with the chopped peanuts.