Preheat your oven to 350°F (175°C) and gather a 9-inch springform pan. In a mixing bowl, combine the red velvet cake mix with melted unsalted butter until crumbly. Press this mixture into the bottom of the pan and bake for 8-10 minutes, until set. Allow it to cool.

Lower oven temperature to 325°F (160°C). Beat cream cheese until smooth; gradually mix in sugar, sour cream, and vanilla. Add eggs one at a time, mixing gently. Fold in cocoa and red food coloring until blended.

Wrap the springform pan with aluminum foil to prevent water from seeping in. Pour cheesecake filling over the cooled crust. Place the pan in a larger baking pan filled with hot water and bake for 60-75 minutes.

Turn off the oven and prop the door open slightly. Let the cheesecake cool for 1 hour in the oven, then refrigerate for at least 4 hours, preferably overnight.

Simmer sliced strawberries with sugar and lemon juice until juices are released, about 5-7 minutes. Mix cornstarch with water, then stir into strawberries and cook until thickened. Let cool.

Release cheesecake from the springform pan. Spoon cooled strawberry mixture over the top. Optionally add whipped cream or whole strawberries as garnish. Slice and serve.