Peanut Butter Sheet Cake - Indiana Connection

Ingredients

• 2 sticks margarine
• 1 cup water
• 1 cup peanut butter
• 2 cups granulated sugar
• ½ tsp salt
• ½ cup buttermilk
• 2 cups flour
• 1 tsp baking soda
• 1 tsp vanilla
• 2 eggs
• 1 stick margarine
• ½ cup peanut butter
• 2 2⁄3 cups powdered sugar