These ooey gooey s'mores bars with layers of Nutella, mini marshmallows, chocolate chips and buttery cookie dough are an irresistible treat for adults and kids alike and perfect when you need to take dessert to a pot luck or barbecue.
Preheat the oven to 180°C/350°F and line a 20cm x 20cm / 7in x 7in square baking dish with parchment paper.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar together until light and fluffy. Scrape the sides of the bowl down with a spatula once or twice while beating to allow everything to incorporate properly.
Add the eggs, one at a time, beating well after each addition. Stir in the vanilla.
Whisk the flour, baking powder and salt together.
Add the dry ingredients and mix until just combined.
Press three quarters of the cookie dough mixture into the prepared baking dish.
Add the Nutella and spread over the cookie dough.
Top with mini marshmallows and chocolate chips. Add dollops of the remaining cookie dough to the top, allowing the marshmallows and chocolate to peak through.
Bake the bars in a preheated oven for 20-25 minutes until golden brown and cooked through.
Remove from the oven and allow to cool for 20-30 minutes before slicing into 16 bars with a sharp knife and serving.
Slicing tip: The marshmallow will stick to the knife so wipe it down with a wet cloth or rinse under hot water in between each slice.