Place potatoes in a large pot of salted water & bring to a boil. Cook for 20 minutes until tender. Drain & mash with milk, 2 Tbsp butter & mustard.
Peel 4 apples, remove cores & cut into large cubes. Place in a saucepan with 1/4 cup water. Bring to a boil then lower heat & simmer for 10 minutes or until tender. When soft add 2 Tbsp sugar & combine to make an applesauce consistency.