In a medium stockpot cover potatoes with water, bring to a boil, boil 20-25 minutes or until tender. Drain, add butter, sour cream, salt and pepper. With electric mixer whip until smooth and fluffy.
In a medium skillet brown ground beef, during last 5 minutes of cook time stir in onions and saute until tender, stir in garlic last 30 seconds of cook time. Drain, stir in gravy and carrot slices.
Unroll sheets of dough, cut into 4 equal strips. On one half place a heaping 1/4 c of mashed potatoes, then top with the same amount of beef mixture. Fold other half of strip over filling, press edges to seal and roll edges upward to seal completely. Place on baking sheet and prick tops with fork.