Heat gas or charcoal grill for indirect cooking. Spray metal muffin pan (with 12 regular-size muffin cups) with cooking spray.
Remove pie crusts from pouches; unroll on work surface or cutting board. With 3-inch round cutter, cut 6 rounds from each crust. Fit rounds into muffin cups, pressing in gently.
In medium bowl, beat cream cheese, cornstarch and sugar with electric mixer on medium speed until well blended. Add egg and vanilla; beat 3 to 4 minutes or until smooth. Slowly stir in whipping cream. Fold in 1/3 cup blueberries. Spoon filling evenly into crust-lined cups.
Place muffin pan on unheated side of two-burner gas grill with one burner heated to medium. (For one-burner gas grill, place pan on grill over low heat. For charcoal grill, move medium coals to edge of firebox; place pan on grill rack.) Cover grill; cook about 17 minutes or until filling is set and crusts are golden brown. Cool 5 minutes; remove from pan to cooling rack. Cool completely.
Garnish mini pies with whipped cream and additional blueberries.