Prepare the Pecan Topping:

Preheat Oven: Preheat your oven to 350°F (175°C). Grease a Bundt pan thoroughly with butter or non-stick spray.

Make the Topping: In a medium bowl, mix the melted butter, brown sugar, cinnamon, and salt until combined. Stir in the chopped pecans.

Spread in Pan: Pour the pecan mixture into the bottom of the prepared Bundt pan, spreading it out evenly.

Prepare the Cake:

Mix Cake Batter: In a large mixing bowl, combine the cake mix, water, vegetable oil, eggs, and vanilla extract (if using). Mix according to the package instructions, typically for 2-3 minutes, until smooth.

Pour Over Topping: Carefully pour the cake batter over the pecan topping in the Bundt pan.

Bake the Cake:

Bake: Bake in the preheated oven for 40-45 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Cool: Allow the cake to cool in the pan for about 10-15 minutes.

Flip and Serve:

Invert the Cake: Place a serving plate over the Bundt pan and carefully flip the pan over to release the cake. Tap gently if needed to ensure it comes out smoothly.

Serve: Let the cake cool slightly before serving warm or at room temperature.