Cheeseburger is a type of food added in Galacticraft 4. It is the ultimate food item, restoring hunger points - that's almost as much as two steaks!
A Cheeseburger also gives a high amount of satiation - a player eating a Cheeseburger should not need to eat anything more for a long time.
So in terms of hunger points and satiation, the cheeseburger gives more than you can get from simply eating all of its ingredients separately.
It is likely that a player will only be able to craft this item after returning to the Overworld from a successful Moon expedition. The cheese is made from Cheese found only on the Moon. Creating the burger also involves beef and milk, which can (probably!) only be found on the Overworld.
In classic science fiction satire novel The Sirens of Titan by Kurt Vonnegut, the protagonist returns to Earth from a long space trip and the only thing he wants is a proper cheeseburger.
A good cheeseburger is also one of radfast's favourite foods - just looking at this makes him feel hungry!