1. First, we prepare the dough for the donuts by heating the milk in the microwave, it must be lukewarm. Pour the milk into a large container with the yeast and add the oil and sugar to the container, mix everything well and then add the flour and salt, mix everything until incorporated.
2. A rather liquid dough will form, we use a mixer to knead for about 10 minutes at medium speed. Pour into a greased dish and cover with a damp cloth. We let it leude for about 30 to 60 minutes, it has to double the size.
3. We move the dough to a surface lightly covered with flour and stretch with our hands. Cut circularly with the help of a mold. We heat enough oil and fry the donuts in it. We only need a couple of minutes for the dough to cook.
4. For the filling, we beat the eggs in a medium bowl, add the cornstarch and icing sugar; Mix until smooth. Add the warm milk to the mixture and stir everything until incorporated.
5. We take the mixture to the fire and stir constantly. Once the mixture thickens, remove from heat and continue stirring. Add La Villita margarine and vanilla extract.
6. Fill the donuts with a thin bag and sprinkle with powdered sugar for the final touch.
7. Enjoy!