1. Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking pan.
2. In a large mixing bowl, combine the chocolate cake mix, pumpkin pie protein powder, water, oil, eggs, and vanilla extract. Mix on medium speed until smooth, about 2 minutes.
3. Pour the batter into the prepared pan and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
4. Allow the cake to cool slightly, then use the handle of a wooden spoon to poke holes all over the cake.
5. Pour the sweetened condensed milk and caramel sauce evenly over the top, allowing it to soak into the holes. Let the cake cool completely.
6. Spread the Cool Whip over the cooled cake and sprinkle with toffee bits and chopped pecans, if using.
7. Refrigerate for at least 2 hours before serving to let the flavors meld beautifully.

This cake is a reminder of the many afternoons spent in my cozy Monterey kitchen, where the aroma of caramel and chocolate would beckon my daughters to sneak a taste before dinner.