To prepare potato topping, place potatoes in a saucepan; cover with water. Bring to a boil; cook 20 minutes or until very tender.
Drain.
Place potatoes, sour cream, and next 5 ingredients (sour cream through pepper) in a large bowl, and beat at medium speed of a mixer until smooth. Keep warm.
Preheat oven to 37
To prepare filling, heat oil in a large nonstick skillet over medium-high heat.
Add carrot; saut 7 minutes.
Add mushrooms; saut 5 minutes.
Add 1 tablespoon sage and garlic; saut 2 minutes.
Sprinkle with flour; cook 2 minutes, stirring until well-blended.
Add broth and wine; bring to a boil. Stir in tomato paste and vinegar.
Add pot roast; cook 2 minutes. Spoon meat mixture into a 2-quart casserole.
Spread potato topping over meat mixture; sprinkle with paprika.