Collect a medium bowl and incorporate the yeast with warm water. Let it rest for 5 minutes until you observe bubbles forming on the surface.
Place melted butter, sugar, evaporated milk, salt, cinnamon, vanilla and eggs into the mixture of yeast. Utilizing a whisk, blend all ingredients together until they are completely unified.
Gradually add the flour and blend until a soft dough is formed. Depending on the kitchen's humidity, you may need to include extra water or flour for texture adjustment. Knead the dough for 8-10 minutes till it turns out smooth and flexible.
Cover the dough with a moist towel and let it be stationary for 15 minutes.
Whilst waiting, preheat the oven to 350°F (175°C). Grease a baking sheet with a generous amount of vegetable shortening as preparation.
After the dough is ready, roll it out on a slightly floured surface at 1/2 inch thickness. Cut into 2 inch circles and use your thumb to press in the center of each circle. Arrange them onto the preheated baking sheet and bake for 15-20 minutes, or until they become a golden brown.
Whilst still warm, mix powdered sugar with cocoa powder to create a delightful glaze. Let them cool down entirely before serving.