1 deep-dish pie crust shell
1/2 c. sugar
1/4 c. brown sugar
1/2 tsp. salt
1/2 c. semi-sweet chocolate chips
1 (12 oz.) can evaporated milk
3 egg yolks, beaten
1 c. sour cream
1 tbsp. butter
3 tbsp. praline liqueur
1 tsp. vanilla extract
1 (8 oz.) container Cool Whip
2 tbsp. semi-sweet chocolate chips for garnish

Preheat oven and baking sheet to 400 degrees. Remove pie crust from freezer. Allow crust to thaw 10-20 minutes. Prick bottom and sides of crust with a fork. Bake on preheated baking sheet for 10 minutes; cool.

In medium bowl, combine sugar, brown sugar, salt and cornstarch; mix well. In a heavy saucepan on medium heat, cook and stir sugar mixture and evaporated milk until mixture thickens and begins to boil. Gradually stir a fourth of hot mixture into beaten egg yolks; add back to remaining hot mixture, stirring constantly.

Stir in sour cream and butter and continue to cook until mixture thickens. Remove from heat and stir in praline liqueur and vanilla, mixing well. Stir in chocolate chips until distributed, but not melted. Pour mixture into pie crust. Let stand 2 minutes; gently swirl mixture with knife blade, creating a marbled effect.

Refrigerate for 30 minutes. Spoon dollops of Cool Whip around edge of pie, leaving the center open with marbling showing. Sprinkle chocolate chips over topping. Refrigerate several hours before serving.