For Raspberry Sauce:
Mix 1 Tbsp. cornstarch and 1/2 cup water until blended. Combine raspberries, 1/4 cup granulated sugar and orange zest in small heavy saucepan. Bring to boil on medium heat, stirring frequently. Use back of spoon to lightly crush raspberries; stir in orange juice. Return to boil. Stir in cornstarch mixture; simmer 5 min., stirring frequently. Remove from heat. Strain. Refrigerate until ready to use.
For Blueberry Sauce:
Mix remaining 1-1/2 Tbsp. cornstarch and 1-1/2 Tbsp. water in small bowl; stir in 1/2 cup blueberries. Combine remaining 1-1/2 cups blueberries, remaining 1/4 cup granulated sugar, lemon zest and salt in medium heavy saucepan. Use back of spoon to lightly crush berries. Bring to boil on medium heat, stirring frequently. Stir in cornstarch mixture; simmer 5 min., stirring frequently. Remove from heat. Add butter; stir until melted. Refrigerate until ready to use.
For each serving:
Blend 4 tsp. milk, 1 rounded cup ice cream and 1 rounded tsp. OREO Pieces in blender until smooth.
Drizzle 1 Tbsp. Raspberry Sauce down inside of tall chilled glass; fill with shake. Top with 1 Tbsp. Blueberry Sauce, 3/4 tsp. Variegate and 1 strawberry half.