Combine first 3 ingredients, tossing well. Place a large nonstick skillet over medium-high heat. Coat shrimp mixture with cooking spray. Add to skillet, and cook 2 minutes, stirring often. Remove from heat.
Combine soup and half-and-half in a large bowl, stirring with a whisk. Add shrimp mixture, potato blend, basil, and salt, tossing gently. Pour mixture into a 1 1/2-quart square baking dish coated with cooking spray.
Cut phyllo pastry in half crosswise. Work with only one sheet at a time, keeping remaining sheets covered with a damp towel. Coat one side of each sheet with cooking spray, and place lengthwise, coated side up, over shrimp mixture. Repeat procedure with remaining phyllo pastry, alternately placing phyllo crosswise and lengthwise over dish. Fold edges under, and gently press against sides of baking dish.
Bake at 375° for 30 to 35 minutes or until golden.