A character is partly defined by a Trademark Favorite Food that they crave and eat, all the freakin' time. Usually in a way that makes you suspect that they're addicted to the substance, and they may have developed their addiction from the first time they tried it. If they're a One-Note Cook, they'll typically be good at making it.
Sometimes justified if the item is a Power-Up Food for the character.
When a character exhibits an obsession for food that corresponds with a stereotype for their race or culture, it is usually considered a Discredited Trope unless played to lampoon the stereotype.
See Also: Stock Animal Diet, which applies this to an entire species of animal; Hollywood Cuisine, which applies this to an entire culture (Brits Love Tea is a subtrope); and Must Have Caffeine, the coffee-specific version. If the answer is "every food", you have a Big Eater. If it is "everything, no matter if food or not", you have an Extreme Omnivore. A specific, sometimes overlapping version of this trope is someone who has a Sweet Tooth. If they talk about that food all the time, they're Obsessed with Food. For a darker and more specific version look at I'm a Humanitarian. See also Impossibly Delicious Food. May overlap with Comfort Food in cases where the comfort food is the character's TFF. Likely to overlap with Far-Out Foreigner's Favorite Food.
Compare Your Favorite and Drink-Based Characterization. Contrast with Does Not Like Spam. If a Big Eater character passes up on their trademark favorite food, it's a sign that things have gotten serious.