Potato Scones

Ingredients

• 2 cups self-raising flour
• 1/4 tsp mustard powder
• 1 1/2 tsp baking powder
• 1/4 tsp salt
• 2 tbsp reduced-salt margarine
• 1/4 cup low-fat milk (or more as needed)
• 3/4 cup cold mashed potatoes ((without any milk or butter added))
• milk or beaten egg (to glaze)
• 2 tsp oatmeal (to sprinkle)