Preheat the oven to 180 degrees C/350F an grease and line your pan.

Place the flours, bicarb and chocolate chips into a medium sized bowl and stir until combined and the chocolate chips have a good coating of flour on, leave to one side.

Place the butter and sugars into a large bowl or the bowl of your stand mixer and beat until light and fluffy, about 2 mins on med-high speed.

Add in the eggs and vanilla extract and, scraping down the sides as necessary, mix until well incorporated and smooth, about 1 min on med-high speed.

Tip in the flour mix and mix on low until a dough forms.

Reserve 1 cup of cookie dough and tip the rest into the 9x9 inch pan. Smooth a little to make sure the whole pan is covered and then sprinkle the chopped fudge bars all over.

Crumble the reserved cup of dough on top of the fudge bars and then pour the condensed milk over the whole pan.

Place in the oven for 25-30 minutes until risen, lightly golden around the edges and the centre is almost set. The condensed milk will be slightly browned around the edges and bubbling.

Leave to cool completely in the pan before removing and slicing into bars.

Bars are best the day you make them, but will keep in an airtight container in the fridge for up to 2 days.