Position racks in the upper and lower thirds of the oven and preheat to 450 degrees F. Place the carrots on a large sheet of foil; drizzle with 2 tablespoons melted butter and season with salt and pepper. Fold up the edges of the foil and add 1/4 cup water, then seal into a packet. Set on a baking sheet and roast on the bottom oven rack until tender, 25 minutes.
Meanwhile, mix the cornflakes, the remaining 2 tablespoons melted butter, the lemon zest and 1/4 teaspoon each salt and pepper in a shallow dish. Whisk 2 tablespoons mustard and the egg white in another dish. Coat the turkey in the mustard mixture; dredge in the cornflake mixture. Place on a wire rack set on a baking sheet. Roast on the top oven rack until cooked through, 15 minutes.
Combine the cranberries, pear, sugar, lemon juice and 2 tablespoons water in a small saucepan; bring to a boil, stirring. Reduce the heat to medium low; simmer until the cranberries burst, 5 minutes. Transfer to a blender, add the remaining 1 teaspoon mustard and puree until smooth. Season with salt and pepper. Serve with the turkey and carrots.