Preheat oven to 350 degrees F.
Line 13×9? baking pan with foil and grease or spray with cooking spray.
In medium bowl, combine the flour and 3/4 cup of brown sugar.
Cut in softened butter until mixture is crumbly.
Press mixture into bottom of prepared pan.
Bake in preheated oven for 10 minutes.
In bowl with electric mixer, beat the cream cheese and granulated sugar until smooth.
Add 1 egg and beat until combined.
Stir in melted and cooled chocolate and vanilla extract and mix to combine.
Pour over baked crust.
Bake 15 more minutes, then allow to cool for 10 minutes.
Sprinkle dark chocolate chips over chocolate cheesecake layer.
In another bowl, whisk together brown sugar, corn syrup, melted butter and 3 eggs. Stir in 1 1/2 cups of chopped pecans.
Pour this over chocolate chips and baked cream cheese mixture, then bake for 40-45 more minutes, or until center is set.
Cool completely in pan.
Once cooled, cut into squares.
Drizzle with caramel sauce (optional but delicious) and serve.