Heat oven to 350°F. Spray 9-inch pie plate with cooking spray. Unroll 1 pie crust in pie plate. Press firmly against side and bottom.
In 2-quart saucepan, heat berries and cherries over medium heat 5 minutes, stirring occasionally; drain. Stir in 1 1/2 cups sugar and the vanilla. Heat 5 minutes longer, stirring constantly; drain. Reduce heat to low. Stir in corn starch mixture; cook 5 minutes longer or until very thick and gooey, stirring constantly, but gently so as not to mash berries. Remove from heat; let cool about 5 minutes.
Spoon dulce de leche into crust-lined pie plate. In small bowl, beat milks, liqueur and 2 medium or 3 small eggs with wire whisk. Gently pour into pie plate. Gently scoop berry mixture on top. Top with second crust. Wrap excess top crust under bottom crust edge. Brush top crust with egg white; sprinkle with 1 tablespoon sugar.
Bake 45 to 50 minutes or until golden brown. Cool 1 hour before serving. Cover and refrigerate any remaining pie.