***BEFORE YOU BEGIN*** Be sure your cream cheese and eggs are at room temperature (set out at least one hour).
Set oven rack to middle. Preheat oven to 300 degrees. Place a 9x13 pan on lower rack. Add 4 cups hot water.
Lightly grease 9-inch springform pan with butter. Line bottom with parchment paper. Combine crushed cookies and melted butter. Press mixture into bottom and slightly up sides of prepared springform pan. Use empty measuring cup to press firmly.
Microwave chocolate and cream at HIGH for 1 1/2 minutes, stirring at 30-second intervals. Remove and stir until chocolate and cream are combined well.
Beat cream cheese at medium speed with a stand mixer for 2 minutes or until light and smooth, scraping down sides with rubber spatula (now put spatula away, no more scraping from this point forward). Add sweetened condensed milk and vanilla, beating until just combined. Add eggs, 1 at a time, beating at low speed just until blended after each addition. Add chocolate mixture, beating just until blended. Pour batter into prepared crust. **DO NOT SCRAPE BOWL**
Bake at 300 degrees for 1 hour and 5 minutes, gently rotate pan 180 degrees midway through baking. Turn oven off and allow cheesecake to stand in oven with door closed for 1 hour. Remove cheesecake from oven; gently run knife around outer edge of cheesecake to loosen from sides of pan. **COOL COMPLETELY** in pan on a wire rack (minimum 1 hour). Cover with waxed paper then plastic wrap and chill 8 to 24 hours.
Remove sides then gently separate parchment lined cake from bottom of pan and slide onto a serving plate. Slowly pour warm Ganache Topping over cheesecake, slightly tipping cake to encourage 'overflow' around the edges. Chill 1 hour before garnishing or serving.