Iced Oatmeal Pie Bars

Name: Iced Oatmeal Pie Bars
Ingredients: For the bars; 1/2 cup (4 ounces) butter; 1 teaspoon cinnamon; 1/2 teaspoon nutmeg; 1/4 teaspoon ginger; 1/4 teaspoon cloves; 1 egg; 1 cup (7 1/2 ounces) brown sugar, lightly packed; 2 tablespoons molasses; 2 teaspoons vanilla extract; 1/2 teaspoon salt; 1 cup (3 1/8 ounces) quick-cooking oats; 3/4 cup (3 1/8 ounces) all-purpose flour; For the frosting; 1/2 cup (4 ounces) butter, softened; 1 1/4 cups (5 ounces) confectioners' sugar; 7 ounces marshmallow cream (fluff); 1 teaspoon vanilla extract