Preheat the oven to 350°F (175°C).
Prepare the cake mix according to package instructions using the melted butter, eggs, and water.
Pour the batter into a greased 9x13 inch baking pan and bake for 30-35 minutes, or until a toothpick comes out clean.
Cool the cake for about 10 minutes, then poke holes uniformly across the top with a fork.
In a medium bowl, mix together the sweetened condensed milk, vanilla, and a pinch of salt.
Pour the condensed milk mixture evenly over the poked cake, allowing it to soak in completely.
While the cake absorbs the milk, prepare the praline topping by combining heavy cream, brown sugar, and pecans in a saucepan.
Bring the mixture to a gentle boil and stir continuously for about 5-7 minutes until it thickens slightly.
Once thickened, remove the praline topping from heat and allow it to cool for a few minutes before pouring over the cake.
Spread the praline topping evenly over the cake and let it sit for at least an hour before serving.