Heat oven to 350°F. Wrap outside of 9- to 10-inch springform pan with aluminum foil. Lightly grease inside of pan. Set aside.
Combine all crust ingredients in bowl. Press onto bottom and 1 inch up sides of prepared pan. Bake 8-12 minutes or until set. Cool completely.
Melt chocolate chips in 2-quart saucepan over low heat, stirring occasionally, 5-6 minutes or until melted. Cool 15 minutes.
Combine cream cheese, 3/4 cup sugar and red food coloring in bowl. Beat at medium speed, scraping bowl often, 2-3 minutes or until creamy. Gradually add 1 egg at a time, beating well after each addition. Add melted chocolate, 1/2 cup sour cream and 2 teaspoons vanilla; beat at low speed 1-2 minutes or until well mixed.
Pour cheesecake mixture into baked crust. Place cheesecake onto center rack of oven. Place pan of warm water on rack below cheesecake to prevent cracking. Bake 80-90 minutes or until just set 2 inches from edge of pan.
Combine 1 1/2 cups sour cream, 2 tablespoons sugar and 1 teaspoon vanilla in bowl. Spread evenly over hot, partially baked cheesecake. Continue baking 5 minutes. Let stand uncovered 30 minutes or until cooled.
Loosen sides of cheesecake by running knife around inside of pan. (Do not remove side of pan.) Loosely cover; refrigerate 8 hours or overnight. Remove side of pan. Garnish cheesecake with chocolate curls, if desired. Store refrigerated.