Preheat oven to 350°F (175°C) and grease a 9x13-inch baking pan. In a large mixing bowl, combine the yellow cake mix, eggs, and water (or milk). Pour into prepared pan and bake for 25–30 minutes or until a toothpick comes out clean. Let cool for 10 minutes.

Once slightly cooled, poke holes throughout the top of the cake, spacing them 1-inch apart. Ensure the holes go all the way to the bottom.

In a saucepan, combine the brown sugar, butter, and heavy cream over medium heat. Stir until it reaches a gentle boil for about 2–3 minutes. Cool slightly before pouring over the poked cake.

Cover the cake and refrigerate for at least 2 hours to allow flavors to meld. Overnight is ideal.

Prepare the topping by chilling a bowl, then combining heavy cream and powdered sugar. Beat until soft peaks form.

Spread the whipped cream over the chilled cake, then sprinkle with toasted pecans.

Slice into squares and serve. Optionally chill for a few more minutes before serving.