Preheat the oven to 350 degrees F (175 degrees C). In a small bowl, mix together the chocolate cookie crumbs and melted butter. Press into the bottom of a 9 inch springform pan. Bake for 8 minutes; cool on wire rack.

For the vanilla-white chocolate filling: Melt white chocolate in a metal bowl over barely simmering water, or in a glass bowl in the microwave, stirring frequently; set aside. In a medium bowl, beat 8 ounces of cream cheese and 1/4 cup sugar until smooth. Mix in 1 egg and 1/2 teaspoon of vanilla until blended. Mix white chocolate into the batter and set aside.

For the dark chocolate filling: Melt chocolate in a metal bowl over barely simmering water, or in a glass bowl in the microwave, stirring frequently; set aside. In another bowl, beat 8 ounces of cream cheese and 1/4 cup sugar until smooth. Mix in 1 egg and 1/4 teaspoon of vanilla until blended. Stir in melted chocolate.

For the strawberry filling: In a third bowl, mix together 8 ounces cream cheese and 1/4 cup sugar until smooth. Blend in 1 egg and 1/2 teaspoon of strawberry extract; stir in mashed strawberries.

Preheat the oven to 400 degrees F (200 degrees C).

Pour the white-chocolate vanilla cheesecake batter into the prepared crust. Layer with the dark chocolate and strawberry batters (see Cook's Notes).

Bake for 10 minutes in the preheated oven, then reduce the temperature to 300 degrees F (150 degrees C), and continue baking for 50 minutes, or until center is nearly set when jiggled.

Remove pan from the oven, immediately run a paring knife around the edge to loosen, and let cool completely. Refrigerate until chilled before removing from the pan.