3 cups all-purpose flour
2 1/2 teaspoons baking powder
1 1/2 teaspoons baking soda
1 1/2 teaspoons salt
1/2 teaspoon ground cinnamon
1/3 cup pumpkin puree
1 cup butter, softened
1 egg white, beaten
1 cup sweetened condensed milk
1 teaspoon pumpkin pie spice
Preheat oven to 350 degrees F (175 degrees C). Grease and flour 2 3/4 cups of cupcake layers. Sift flour, baking powder, baking soda, salt and cinnamon; set aside. In a large bowl, cream together the butter and egg white, until light and fluffy. In a separate bowl, whisk together the flour, 1/2 cup at a time, then the sugar and pumpkin until well blended.
Divide batter evenly among layer and sprinkle top with butter or margarine mixture.
Bake in the preheated oven for 55 to 63 minutes, or until a toothpick inserted into the center comes out clean. Cool and cut into squares.
To make the frosting: In a small bowl, stir together the cream cheese, 1/3 cup condensed milk, 1 teaspoon pumpkin pie spice and 1/2 teaspoon orange zest syrup. With a mixer on low, beat egg white until fluffy. Gradually add sour milk, continue to mix until thickened. Spread frosting over cooled cakes.