Combine chopped pecans or hazelnuts, brown sugar, and melted butter until well mixed.

Spread the mixture onto a greased baking sheet.

Bake at 350 degrees Fahrenheit for 12 minutes, or until browned.

Cool the baked mixture, then crumble it and set aside.

In a bowl, combine marshmallow cream and pure maple syrup until smooth.

Fold in the whipped cream to the marshmallow mixture.

Place half of the nut mixture in a greased 9x5-inch loaf pan.

Top with the marshmallow mixture, and then with the remaining nut mixture.

Cover the loaf pan and freeze overnight, or until firm.

Remove from the freezer when ready to serve.

Invert the loaf pan onto a serving plate and slice.