Preheat your oven to 350°F (175°C). Grease and flour three 9-inch round cake pans.

In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt.

Add the eggs, milk, vegetable oil, and vanilla extract to the dry mixture and beat for 2 minutes until smooth.

Carefully stir in the boiling water until the batter is thin and silky.

Fold in the chopped pecans, ensuring even distribution.

Divide the batter among the prepared pans and bake for 30-35 minutes or until a toothpick comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then turn them onto wire racks to cool completely.

Whip the cold heavy cream until it thickens, then gradually add powdered sugar and vanilla extract until stiff peaks form.

To assemble, layer one cake, add caramel sauce and whipped cream, repeat with the next layer, then finish with whipped cream and caramel on top.

Chill the cake in the refrigerator for at least 30 minutes before serving.