Grease and line an 18cm microwave safe baking dish.
In a bowl, cream together butter, sugar and vanilla until well mixed then stir in eggs, one at a time. Melt the chocolate in the microwave on half power, stirring every 30 seconds, until melted. Stir in the hazelnut spread until combined then sir into the butter mixture.
Fold flour and most of the hazelnuts into the butter mixture, then pour into the prepared baking dish. Sprinkle over the remaining hazelnuts.
Place a plate upside-down on the microwave turn table then microwave brownies, uncovered, on half power until done, about 15 minutes. Allow to cool then slice and serve with ice cream.
If you can't find roast hazelnuts, just microwave fresh hazelnuts in an oven bag on high for 5 minutes, stopping to shake the bag every minute. When done, just wrap them in a tea towel and rub together to get the skin off.