Preheat oven to 425 F degrees. Butter the muffin tray, or use muffin liners.
In a large bowl combine the flour, baking powder, salt, cinnamon; set aside.
Whisk the eggs and sugar together until combined. Add the melted butter, evaporated milk, vegetable oil and vanilla and continue whisking until well combined.
Fold in the wet ingredients into the dry ingredients and mix together gently. Do not over mix. The batter should be thick and a bit lumpy. Fold in the chocolate chips.
Spoon a large spoonful of the batter into each muffin cup, filling all the way to the top. Sprinkle with coarse sugar such as turbinado sugar, if desired.
Bake for 5 minutes at 425 F degrees, then turn down the oven to 350 F degrees. and bake for another 25 minutes or until the tops are lightly golden brown and the center is set. You can test it by sticking a toothpick into a muffin and it should come out clean.
Allow muffins to cool for 10 minutes in the muffin pan before transferring to a cooling rack and serving.