1/3 pound hazelnuts
1 cup sugar
8 tablespoons unsalted butter (1 stick)
2 eggs
1 cup sour cream
2 teaspoons vanilla extract
1/2 cup banana puree, from 1 or 2 bananas
1 3/4 cups all-purpose flour
2 teaspoons baking powder
1 teaspoon salt
Hazelnut schmear, recipe follows
Whole bananas
3/4 cup butter
1/2 pound dark brown sugar
1/2 cup chopped toasted hazelnuts