Step 1

Heat oven to 425°F. With vegetable peeler, remove 6 strips lemon zest, avoiding white pith; thinly slice crosswise. In small bowl, combine butter, garlic, mustard, lemon zest and 1/2 teaspoon each salt and pepper; set aside.

Step 2

Remove skin from turkey-breast halves and set aside. Rub butter mixture all over turkey breasts. Place one breast half on top of the other, arranging so 1 thick side and 1 thin side are sandwiched together. Wrap breasts in skin and tie with butcher's twine to form log shape.

Step 3

On large rimmed baking sheet, toss shallots with oil and 1/4 teaspoon each salt and pepper. Arrange them in center of sheet and place turkey on top. Roast 60 minutes.

Step 4

Remove from oven and transfer turkey to cutting board. Add potatoes, carrots and parsnips to baking sheet and toss with shallots and 1/2 teaspoon each salt and pepper; arrange in even layer. Place turkey on top of vegetables and roast until turkey registers 160°F on instant-read thermometer and vegetables are golden brown and tender, 35 to 45 minutes more (remove vegetables that are done before turkey).

Step 5

Transfer turkey to clean cutting board and let rest at least 10 minutes before slicing. Serve with pan juices and vegetables.