Nomstrosity

Noun. The word "monstrosity" with the "m" and the "n" cleverly inverted to indicate deliciousness (i.e., that you would nom it. Foods or meals that might be referred to, sarcastically or literally, as nomstrosities because they are huge, filling, rich, hearty, piled high with ingredients or toppings, or ugly to look at, but are also (or inspite of this) delicious would qualify as nomstrosities.

Foods that are delicious despite being an affront to mankind are particular nomstrosities.