Instructions

To make the cookie dough:

1. Spread the flour out on a baking sheet, and toast in an oven heated to 300F/150C for 10 minutes. Leave to cool. 
2. Put the butter, brown sugar, and vanilla extract into the bowl of your stand mixer (or using a handheld electric beater) and beat until creamy and smooth- about 2-3 minutes.
3. Add half of the flour, and beat to combine. With the mixer still running, pour in the condensed milk and beat until fully combined. 
4. Add the rest of the flour, and the salt, and beat to combine. If the dough looks a little dry (give it a taste test to test the texture if you're unsure) add 1-2 tbsp of milk, 1/2 tbsp a time until you get the desired consistency. I didn't add any milk.
5. Add the peanut butter and beat on a low speed until just combined. 
6. Stir in the chocolate chips by hand. 
7. Spread out into a 9"x13" brownie pan {affiliate link} lined with greaseproof paper. Chill in the fridge for one hour. 

To make the topping:

1. Put the chocolate and peanut butter in a heatproof bowl, and heat in the microwave, stirring every 30 seconds, until melted and smooth. 
2. Pour over the top of the cookie dough and spread into an even layer. Chill for a further 2 hours, until the chocolate topping is set.
3. Cut into bars and serve.