Pre-heat the oven to 180C.

Line a 25cm x 25cm tin with baking paper.

Melt the butter and sugar together over a low heat.

Once they are melted, remove from the heat and beat in the peanut butter.

Leave to cool for 5 or 10 minutes.

Meanwhile, put the Nutella and dark chocolate in another bowl and microwave for 20 seconds, take out and stir very well. If it's not melted together, pop back in for another 20 seconds and stir well again. Repeat if you need to, but be really careful not to burn the chocolate. You're trying to make a smooth paste consistency with no lumps.

Go back to your butter, sugar and peanut butter mixture and beat in each egg, one by one.

Stir in the flour.

Put the batter in to the prepared tin and smooth out with a spatula.

Now take your chocolate mixture and using a spoon, dollop (technical term) 4 or 5 lines of it horizontally along the length of the pan.

Now use the edge of a knife to draw lines vertically through these lines, first top to bottom, then bottom to top, about 10cm apart. Taaa-daaa! Pretty pattern ahoy.

Bake for about 20 minutes. A skewer should come out only just clean. You could test at 17 minutes and again at 20 minutes just in case.

As always, remember that depending on your oven it could take up to 10 minutes longer, but please please try not to overcook them. Blondies are always better under-done than over.