Step 1

Preheat oven to 350°F. In microwave-safe medium bowl, heat butter in microwave oven on high 1 minute 15 seconds or until melted. In food processor with knife blade attached, pulse wafers until fine crumbs form. Pour crumbs into butter and stir until crumbs are moist. Pour crumbs into 9-inch springform pan; press crumbs on bottom and 2 inches up side of pan. Bake 10 minutes. Cool crust completely on wire rack. While crust cools, in microwave-safe medium bowl, heat chocolate morsels in microwave oven on high 1 minute 15 seconds or until smooth, stirring every 30 seconds. In large bowl, with mixer on medium speed, beat cream cheese, 1/2 cup sugar and salt 3 minutes, occasionally scraping bowl with rubber spatula. With mixer on low speed, beat in eggs, milk and vanilla until well blended. Add chocolate and beat until combined, occasionally scraping bowl. Pour chocolate mixture into cooled crust. Bake 45 minutes. Cheesecake will still jiggle slightly in center. While cheesecake bakes, in small bowl, stir sour cream and remaining 3 tablespoons sugar until sugar dissolves. Remove cheesecake from oven. Gently spread sour cream mixture evenly on top of cheesecake. Bake 5 minutes longer to set sour cream. Cool cheesecake completely on wire rack. Cover and refrigerate at least 6 hours or up to 2 days before cutting into wedges to serve.

Step 2

Preheat oven to 350°F. In microwave-safe medium bowl, heat butter in microwave oven on high 1 minute 15 seconds or until melted. In food processor with knife blade attached, pulse wafers until fine crumbs form. Pour crumbs into butter and stir until crumbs are moist. Pour crumbs into 9-inch springform pan; press crumbs on bottom and 2 inches up side of pan. Bake 10 minutes. Cool crust completely on wire rack.While crust cools, in microwave-safe medium bowl, heat chocolate morsels in microwave oven on high 1 minute 15 seconds or until smooth, stirring every 30 seconds. In large bowl, with mixer on medium speed, beat cream cheese, 1/2 cup sugar and salt 3 minutes, occasionally scraping bowl with rubber spatula. With mixer on low speed, beat in eggs, milk and vanilla until well blended. Add chocolate and beat until combined, occasionally scraping bowl.Pour chocolate mixture into cooled crust. Bake 45 minutes. Cheesecake will still jiggle slightly in center. While cheesecake bakes, in small bowl, stir sour cream and remaining 3 tablespoons sugar until sugar dissolves. Remove cheesecake from oven. Gently spread sour cream mixture evenly on top of cheesecake. Bake 5 minutes longer to set sour cream.Cool cheesecake completely on wire rack. Cover and refrigerate at least 6 hours or up to 2 days before cutting into wedges to serve.