Pumpkin Pie Cake with Cinnamon Frosting

Ingredients

• 1 package yellow cake mix (regular size)
• 3 large eggs, room temperature
• 1 cup water
• 1 cup canned pumpkin
• 1-3/4 teaspoons ground cinnamon, divided
• 1/4 teaspoon ground ginger
• 1/4 teaspoon ground nutmeg
• 2-1/2 cups vanilla frosting
• 1-1/4 cups chopped walnuts
• Additional ground cinnamon