In a medium bowl, combine graham cracker crumbs with granulated sugar and melted butter until the mixture resembles wet sand. Press this mixture firmly into the bottom of a greased 9-inch springform pan, creating an even layer. Set aside to firm up while you prepare the cheesecake filling.

Boil 1 cup of water and steep the Earl Grey tea bags for about 10 minutes, allowing the flavors to fully release. Once steeped, remove the tea bags and let the liquid cool completely to room temperature.

In a large mixing bowl, beat the softened cream cheese and granulated sugar together with an electric mixer until smooth and fluffy, about 2-3 minutes. Gradually blend in the cooled Earl Grey tea, vanilla extract, and sour cream, mixing until combined. Incorporate the eggs one at a time, mixing just until the mixture is smooth.

Pour the rich filling over the prepared crust, spreading it evenly with a spatula. Bake the cheesecake in a preheated oven at 325°F (160°C) for 55-60 minutes until the center is slightly jiggly.

Once baked, turn off the oven and leave the cheesecake inside for about 1 hour to gradually cool down. After this, refrigerate for at least 4 hours, preferably overnight.

While the cheesecake cools, prepare the mulberry sauce by combining mulberries, water, granulated sugar, and lemon juice in a small saucepan. Over medium heat, let the mixture simmer for 10-12 minutes until it thickens. Strain if desired.

After the cheesecake has chilled, carefully remove it from the springform pan. Spoon the cooled mulberry sauce generously over the top. Slice into beautiful pieces and serve.