1. Heat oven to 425 degrees. Fit piecrust into a 9- or 9-1/2-inch removable-bottom tart pan. Line with a double layer of nonstick foil, pressing against side of crust. Bake at 425 degrees for 18 minutes. Remove crust from oven, reduce heat to 375 degrees and remove foil.
2. Meanwhile, blend goat cheese, 6 tbsp of the sugar, the egg and milk in a bowl. Pour into crust. Bake at 375 degrees for 20 minutes or until set.
3. While cheese layer bakes, make topping. Combine remaining 1 cup sugar, the cranberries, cranberry juice, lemon zest and lemon juice in a saucepan. Bring to a boil and cook for 10 minutes over medium heat, stirring occasionally. Remove from heat and pour over baked goat cheese layer. Cool until set.