Answer:
I have one, you have one. If you remove the first letter, a bit remains. If you remove the second, bit still remains. If you remove the third, it still remains.
What must be in the oven yet can not be baked? Grows in the heat yet shuns the light of day? What sinks in water but rises with air? Looks like skin but is fine as hair?
What is it which builds things up? Lays mountains low? Dries up lakes, and makes things grow? Cares not a whim about your passing? And is like few other things, because it is everlasting?
A house full, a yard full, a chimney full, no one can get a spoonful.
When young, I am sweet in the sun. When middle-aged, I make you gay. When old, I am valued more than ever.
This food is a tortilla filled with cheese and sometimes chicken before being heated or cooked.