1. Preheat your oven to 350°F (175°C). Line a 15×10-inch jelly roll pan with parchment paper and lightly grease it.
2. In a bowl, sift together the flour, cocoa powder, baking powder, and salt. Set aside.
3. In a large mixing bowl, beat the egg yolks with 1/2 cup of the sugar until thick and pale. Stir in vanilla extract and milk.
4. Gently fold in the dry ingredients, followed by the melted butter.
5. In another bowl, beat the egg whites until soft peaks form. Gradually add the remaining 1/4 cup sugar, beating until stiff peaks form.
6. Carefully fold the egg whites into the chocolate batter, being mindful not to deflate the mixture.
7. Pour the batter into the prepared pan, spreading evenly. Bake for 12-15 minutes, or until the cake springs back when gently touched.
8. While the cake is baking, prepare a clean kitchen towel dusted with cocoa powder.
9. After baking, immediately invert the cake onto the towel and gently peel off the parchment paper. Roll the cake up with the towel from the short end. Allow to cool completely.
10. For the filling, combine evaporated milk, brown sugar, egg yolks, and butter in a saucepan. Cook over medium heat, stirring constantly, until thickened, about 10 minutes. Remove from heat and stir in vanilla, coconut, and pecans. Let cool.
11. Unroll the cooled cake and spread the filling evenly over the surface. Reroll the cake without the towel. Transfer to a serving platter, seam side down.

Rolling up that warm cake in a towel always reminds me of my abuela teaching me patience and care, as we waited for her tortillas to cool, sharing stories and laughter.