1. Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking dish.
2. In a large mixing bowl, combine the butter pecan cake mix, water, vegetable oil, and eggs. Beat until smooth, then fold in the chopped pecans.
3. Pour the batter into the prepared baking dish and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
4. While the cake is baking, prepare the praline sauce. In a medium saucepan, melt the butter over medium heat. Stir in the brown sugar, heavy cream, and vanilla extract. Bring to a gentle boil, stirring occasionally, until the sugar has dissolved and the sauce is smooth.
5. Once the cake is done, remove it from the oven and let it cool slightly. Using the handle of a wooden spoon, poke holes all over the cake, about 1 inch apart.
6. Pour the sweetened condensed milk over the cake, allowing it to soak into the holes.
7. Next, pour the warm praline sauce over the cake, spreading evenly with a spatula to ensure it seeps into the holes.
8. Let the cake cool completely, then spread the whipped topping evenly over the top.
9. Refrigerate for at least 2 hours before serving to allow the flavors to meld beautifully.

Remember, patience is key, as my cooking adventures have taught me. The longer the cake sits, the better it tastes!