BAKE pastry shells according to pkg. directions.
MIX blueberries, 3/4 cup sugar, cornstarch, water and lemon zest in saucepan. Cook and stir over medium heat until mixture boils and thickens. Cover and refrigerate.
MIX 1/3 cup sugar and flour in saucepan. Stir in milk. Cook and stir over medium heat until mixture boils and thickens. Remove from heat and gradually stir half of hot mixture into egg. Return egg mixture to saucepan. Cook and stir over medium heat 1 min. Remove from heat and stir in butter and vanilla. Place plastic wrap directly onto surface of pastry cream and refrigerate 45 min.
SPOON 1 tbsp. blueberry mixture into each pastry shell. Top with 1 tbsp. pastry cream and 1 tbsp. blueberry mixture. Repeat layers. Top with remaining pastry cream and whipped cream.