Pour the bread flour into a mixing bowl and add the salt and yeast on opposite sides.  Stir in each one, making sure that the salt doesn't touch the yeast directly.

Add the sugar, butter, eggs, and vanilla extract and mix until a clumpy mixture has formed.

Gradually trickle in the warm milk and mix with your hand to form a slightly sticky dough.  Keep mixing until there's no more flour in the bottom of the bowl.

Knead the dough until it's no longer sticky and is very smooth, about 10-15 minutes.  Use a bench scraper if needed to help with the kneading.  The dough should also pass the windowpane test, which means that you can stretch a piece of dough until it's translucent without it tearing.

Shape the dough into a ball, place it in a buttered bowl, cover with plastic wrap, and let it rise in a warm place until it's doubled in size, about 2 hours.

Meanwhile, prepare the topping.  Sift the flour and icing sugar into a bowl and blend in the lard and vanilla extract to form a paste.  Knead the paste a few times until it's very smooth.

Divide the paste into 5 equal pieces.  Leave one piece plain, and knead 2-3 tablespoons of cocoa powder into another one to make it chocolate flavored.  Color the remaining pieces pink, yellow, and blue with the gel food coloring.

Place 24 colored cupcake liners in two muffin pans.

Once the dough has doubled in size, punch it down and divide it into 24 equal pieces.  Roll each one into a tight ball and place in the paper liners.

Divide each ball of paste into 5 pieces, and pat each piece into a thin disc.  Place each disc on top of a ball of dough and use a small sharp knife to cut curved parallel lines into the paste to create the distinctive concha pattern.

Let the manteconchas prove uncovered at room temperature for 30-45 minutes, until the dough springs back when gently prodded with a fingertip.

Bake the manteconchas at 375 F for 15-20 minutes, until they have an internal temperature of 190 F on a meat thermometer.  Let them cool on a wire rack for a few minutes before serving with a hot cup of coffee or hot chocolate.