Prepare the Blondie Base:

1. Preheat the oven to 350°F (175°C). Grease a baking pan.
2. Melt butter with salt and brown sugar in a saucepan over medium heat. Remove from heat and mix in the egg and vanilla extract.
3. Stir in the flour and fold in the chocolate chips.
4. Spread the mixture evenly in the prepared pan and bake for 15-20 minutes, or until golden brown. Allow to cool completely.

Assemble the Cheesecake Layer:

1. In a large mixing bowl, beat the cream cheese with cornstarch, sugar, and salt until smooth.
2. Add whipping cream, a few drops of blue food coloring, and vanilla extract. Mix until well combined.
3. Gradually add eggs one at a time, mixing just until incorporated.
4. Gently fold in the crushed Oreo cookies.
5. Pour the cheesecake mixture over the cooled blondie base.

Baking and Cooling:

1. Bake the cheesecake in a water bath at 300°F (150°C) for 50-60 minutes or until the center is set.
2. Cool in the oven with the door slightly open for about an hour, then refrigerate overnight to achieve the best texture and flavor.

Adding the Ganache:

1. In a microwave-safe bowl, microwave the chocolate chips, heavy whipping cream, and a pinch of salt in 30-second intervals, stirring each time, until smooth.
2. Spread the ganache evenly over the chilled cheesecake.
3. Decorate with extra Oreo pieces or cookie crumbs if desired.