Preheat the oven to 350°F (175°C). Combine flour, softened butter, sugar, and pecan bits in a mixing bowl. Stir until the mixture becomes crumbly and uniform. Press the mixture firmly into the bottom of a 9×13-inch (23×33 cm) rectangular pan. Bake for approximately 15 to 18 minutes or until the crust achieves a light golden hue. Allow to cool entirely.

Blend the softened cream cheese with powdered sugar in a mixing bowl until a smooth texture forms. Separately, whip the chilled heavy cream until stiff peaks hold. Gently fold the whipped cream into the cream cheese mixture. Distribute this layer evenly over the cooled crust.

In a medium bowl, whisk together both instant pudding powders and the milk for around 2 minutes, or until the mixture thickens. Carefully spread the pudding layer over the cream cheese layer.

Evenly spread whipped topping over the surface of the pudding. Scatter with reserved chopped pecans, and optionally add a sprinkle of chocolate shavings or a light drizzle of chocolate syrup.

Refrigerate for no less than 2 hours before slicing into portions. Serve chilled for optimal texture and flavor.