Preheat your oven to 350°F (175°C) and grease and line a 15x10-inch jelly roll pan with parchment paper.

Whisk together the flour, cocoa powder, baking powder, baking soda, and salt in a medium-sized bowl.

Beat the eggs and sugar in a large mixing bowl until light, fluffy, and pale, about 3-5 minutes.

Mix in the vanilla extract and vegetable oil into the egg and sugar mixture until fully incorporated.

Fold the dry ingredients into the wet mixture, ensuring no lumps while maintaining airiness.

Pour the batter into the prepared jelly roll pan and spread it evenly.

Bake for approximately 12 minutes until the cake springs back lightly when touched.

Let the cake cool in the pan for 5 minutes, then turn it out onto a kitchen towel sprinkled with powdered sugar.

In a saucepan over low heat, combine evaporated milk, brown sugar, butter, and vanilla extract, stirring for 5-7 minutes.

Stir in the coconut flakes and chopped pecans into the filling mixture until blended.

Spread the filling over the unrolled cake and roll it back up tightly, starting from one end.

Wrap the rolled cake in plastic wrap and refrigerate for at least 30 minutes before serving.