Preheat the oven to 175°C and line a baking sheet with greaseproof paper.

Melt the butter and allow it to cool for about 5-10 minutes until it is just slightly warm.

In a large mixing bowl or stand mixer, beat together the melted butter, brown sugar and caster sugar until smooth.

Add the vanilla extract and egg and mix until fully combined.

In a separate bowl, whisk together the flour, bicarbonate of soda and salt.

Add half of the dry ingredients to the wet ingredients and mix until just combined. Add the remaining flour mixture and stir until a soft cookie dough forms.

Fold in the white chocolate chips, rainbow sprinkles and crushed golden Oreos.

Scoop about 1½ tablespoons of dough and flatten it in your hand. Place a golden Oreo in the centre, then cover it with another 1½ tablespoons of dough, sealing the edges so the biscuit is completely enclosed.

Roll into a smooth ball and place onto the prepared baking sheet, leaving about 5-7 cm between each cookie.

Sprinkle a few extra rainbow sprinkles and crushed Oreos on top if you like.

Bake for 10-12 minutes, until the edges are golden and the centres are still slightly soft.

Allow the cookies to cool on the baking sheet for 5-10 minutes, then transfer to a wire rack to finish cooling.