This is a decadent versin of an after-dinner mint! The sour cream gives this cheesecake and exceptionally light and creamy texture. Prep time is a guesstimate, and cook time does not include chill time.
Heat oven to 350ºF. Wrap bottom and sides of a 9-inch springform pan with wide heavy duty foil.
In a medium bowl, stir together cookie crumbs and melted butter until crumbs are evenly moistened. Press evenly into bottom and 1 inch up sides of pan. Bake 6-8 min or until set; cool on wire rack.
Place 6 oz. of chocolate in medium bowl over a saucepan of simmering water. Stir frequently until chocolate is smooth and melted; remove bowl from saucepan.
In a large bowl, beat cream cheese and sugar at low speed until smooth.
Beat in flour. Beat in 2 of the eggs just until combined; repeat with remaining 2 eggs. Scrape down sides of bowl.
Beat in sour cream and vanilla just until blended.
Reserve 2 cups of this batter in another medium bowl; stir in 1 teaspoons peppermint extract.
Stir the melted chocolate into the batter in the large bowl until completely blended; pour into crust.
Place pan in a large shallow roasting pan or broiler pan. Fill with enough hot tap water to come halfway up sides of the springform pan.
Bake 35 minute. Carefully slide out oven rack several inches and pour the reserved peppermint batter evenly over cheesecake.
Bake 25 min or until edges are puffed and top is dry to the touch. Center should move slightly when pan is tapped but should not ripple as if liquid.
Remove cake from water bath; remove foil. Place on a wire rack; cool to room temperature, about 2 hours.
Meanwhile, place 6 oz. finely chopped chocolate in another large bowl. Place cream, 2 Tbs. butter and corn syrup in heavy medium saucepan; heat over medium heat 2-3 min or until hot but not boiling. Remove saucepan from heat as soon as first bubble appears.
Pour over chocolate and let stand for 1 min to soften. Stir until mixture is smooth and chocolate is melted.
Stir in 1/2 teaspoons peppermint extract. Cool to room temperature, about 1 hour.
Pour glaze over cooled cheesecake in pan, spreading evenly over top; refrigerate at least 6 hours before serving.
Store in refrigerator. Cheesecake can be made up to 3 days ahead; stor in refrigerator.