Hazelnut butter refers to a creamy spread made by grinding roasted hazelnuts into a smooth consistency. It resembles peanut butter but with a roasted nutty flavor that comes from hazelnuts. Full definition
The topping is a mixture of chocolate hazelnut butter, dark chocolate, and heavy cream, then it's finished with toasted hazelnuts and a sprinkle of coarse sea salt. (ambitiouskitchen.com)
I have to say that this one, where the pan browned sprouts are tossed with hazelnut butter infused with lemon zest is the most delicious way I have discovered thus far. (cookandbemerry.com)