1. Pre heat your oven to 160c fan.
2. Line your tin with butter and parchment paper, add the golden syrup to the tin and place it in the oven for ten minutes.
3. Melt the butter in the microwave or in a pan and add both sugars to your bowl and mix with a hand whisk or hand mixer.
4. Add the eggs, egg yolks and vanilla then mix again.
5. Add the flour to the bowl and fold it in partially, then add the chocolate chips and continue to fold the rest of the flour into the batter.
6. Scoop the blondie batter into the tin and press it down so it is flat and even.
7. Add the Nutella to the top of the blondie and use a cocktail stick to swirl the Nutella in the blondie.
8. Bake the blondies for 25 – 30 minutes and let them cool for 15 minutes before placing them in the fridge for at least 5 hours (or overnight) before cutting them up.