Step 1

Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, line a 8" square tin with greaseproof paper. I grease the tin first with a little butter to help the paper stick to it

Step 2

To make the cookie dough base, using a stand mixer with the paddle attachement, or by hand with a spoon, mix the butter and sugar together until fluffy and well combined

Step 3

Add the milk and vanilla extract and mix well until combined

Step 4

Then add the plain flour and salt, and mix until a dough forms

Step 5

Finally mix in the chocolate chips until well distributed

Step 6

Press the cookie dough into the bottom of the tin using your hands, try and make it an even layer

Step 7

Put the cookie dough in the fridge while you make the brownies, or for at least 30 minutes

Step 8

To make the brownie batter, melt the dark chocolate and butter together in a pan on a low heat. When fully melted, stir together and remove from the heat. Let it cool for 10 minutes

Step 9

In a mixing bowl whisk together the eggs and light brown sugar until frothy, by hand with a whisk or with an electric whisk

Step 10

Add the melted chocolate and butter mixture to the egg and sugar mixture, whisking constantly as you pour it in

Step 11

Add the plain flour and cocoa powder, and whisk in gently

Step 12

Then stir in the chocolate chips

Step 13

Take the tin with the cookie dough in it out of the fridge and cover them with the Biscoff sandwich biscuits, you may need to chop some of the biscuits in half to fully cover the cookie dough

Step 14

Pour the brownie batter over the top, then add spoonfuls of the Biscoff spread all over. Use a butter knife to swirl it around a little bit - don't over mix

Step 15

Bake for 45-55 minutes, the brownie layer should not wobble (or only very slightly) when you gentle shake the tin

Step 16

Let the brownies cool completely in the tin before removing and slicing up

Step 17

Store in an airtight container in a cool place and eat within 3 days, they can also be frozen