In a hot saute pan, add the oil. Cook the onion, garlic, and jalapeno for 3 minutes, or until the onions have become translucent. Add the huitlacoche, and cook for another 3 minutes. Add the chopped epazote, and season with salt and pepper. Set aside to cool.
Preheat oven to 350 degrees F.
Arrange the crepes and other ingredients in assembly-line fashion: crepes, filling, cheese, and crema. Spread 1 tablespoon of sour cream on an open crepe, sprinkle a heaping tablespoon of the huitlacoche filling, cover with a sprinkle of cheese, and roll the crepe into a tube. Repeat process with the remaining ingredients.
Spread a thin layer of sour cream on the bottom of an oblong 8 by 12-inch glass baking dish. Place the rolled crepes, seam side down, close, but not over lapping, in the bottom of the pan. Sprinkle with the remaining cheese and crema. Bake in the oven until the cheese is melted and crepes are heated through, about 30 minutes. Drizzle with a little truffle oil.
In a large mixing bowl, whisk the milk, eggs, and melted butter. Increase speed and whip for 1 minute. In another bowl, sift the dry ingredients together, and slowly begin to add the dry ingredients to milk mixture. When well mixed, strain the batter into a spouted measuring cup.
In a non-stick pan, spray a little non-stick spray or coat lightly with butter and pour in about 1/4 cup of batter. Immediately start tilting pan, covering the bottom of the pan with batter. Cook until the crepe turns pale brown, then flip with a spatula, cook for 20 seconds more, and remove from the pan onto a paper towel to cool. Repeat the process with the remaining batter.