Preheat the oven to 350°F. Grease a 15x10-inch jelly roll pan and line it with parchment paper, greasing the parchment as well.

In a large bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Mix well.

In another bowl, whisk together the eggs, milk, oil, and vanilla extract. Gradually add the wet ingredients to the dry ingredients, mixing until just combined.

Carefully stir in the boiling water until the batter is smooth.

Pour the batter into the prepared pan and spread it evenly. Bake for 15-20 minutes or until a toothpick inserted in the center comes out clean.

Remove from the oven and let it cool in the pan for about 5 minutes.

While the cake is cooling, prepare the filling by combining the coconut, pecans, sweetened condensed milk, and vanilla extract in a medium saucepan over medium heat. Cook for about 5-7 minutes, stirring constantly until thickened. Remove from heat and let cool.

Once the cake has cooled slightly, invert it onto a clean kitchen towel dusted with powdered sugar. Carefully peel off the parchment paper.

Spread the coconut-pecan filling evenly over the cake, leaving a small border around the edges.

Starting from one end, roll the cake tightly with the towel, using it to help shape the roll. Wrap the rolled cake in plastic wrap and refrigerate for at least 1 hour.

For the frosting, beat the heavy cream, powdered sugar, and vanilla extract in a mixing bowl until stiff peaks form.

After chilling, remove the cake roll from the refrigerator and unwrap it. Spread the whipped cream frosting over the top of the roll.

Slice into pieces and serve.