Spoon twelve tablespoons of white chocolate spread onto a parchment-lined baking sheet and freeze for at least one hour.

In a stand mixer, beat cold butter with brown and granulated sugar until crumbly, about 2-3 minutes. Stir in both types of chocolate.

In a separate bowl, whisk together plain flour, self-raising flour, black cocoa powder, crushed Oreos, baking powder, and salt. Blend into the buttery mixture until thick.

Add in the eggs, mix until combined, weigh and divide into 125g portions. Insert frozen dollops of white chocolate spread into each ball and roll in crushed Oreos.

Place cookies on a plate or container and freeze for at least 4 hours (overnight preferred).

Preheat the oven to 190°C (fan), arrange frozen cookies on a baking sheet and bake for about 16 minutes.

Cool slightly before serving to enjoy the molten center.