4 medium bananas, peeled and sliced into 1/2 inch pieces
6 tablespoons light brown sugar
1/4 cups hazelnuts
1 cup ice cubes
1/4 cups milk
1/4 cups dark rum or hazelnut liqueur
2 tablespoons chopped hazelnuts, for garnish (optional)
Place the sliced bananas in a sealed plastic bag and put them in the freezer for 1 hour.
Place the brown sugar and 1/4 cups hazelnuts in a blender and grind together until fine.
Place the frozen bananas, ice cubes, milk, and rum in the blender with the sugar and nut mixture.
Blend until smooth.
Pour the smoothies into 4 goblets or tall glasses.
Garnish with chopped nuts, if desired.