Butternut Squash Cake with Butter Rum Frosting

1 1/4 cups packed brown sugar
1 cup vegetable oil
2 tsp vanilla
3 eggs
2 1/2 cups all purpose flou
r1 1/2 tsp baking soda
1 1/2 tsp pumpkin pie spice
1/2 tsp salt
2/3 cup buttermilk
2 cups shredded peeled butternut squash
1/2 cup dried cranberries
1/2 cup toasted hazelnuts

1/2cup butter or margarine, softened
4oz (half of 8-oz package) cream cheese, softened
2tablespoons rum or 2 teaspoons rum extract plus 4 teaspoons milk
4cups powdered sugar
1/4cup chopped toasted hazelnuts (filberts)

Heat oven to 350°F. Spray bottom and sides of 13x9-inch pan with baking spray with flour.
In large bowl, beat brown sugar, oil, vanilla and eggs with electric mixer on medium speed until creamy. On low speed, beat in flour, baking soda, pumpkin pie spice and salt until mixed. Add buttermilk; beat on low speed until mixed. Beat on medium speed 1 minute longer. Stir in squash, cranberries and hazelnuts. Pour into pan.
Bake 45 to 55 minutes or until toothpick inserted in center comes out clean. Cool completely, about 1 hour.
In medium bowl, beat butter and cream cheese on medium speed until creamy. Add rum and powdered sugar; beat on low speed until mixed. Beat on medium speed until smooth and creamy. Frost cake. Sprinkle with 1/4 cup hazelnuts. Store covered in refrigerator.