This will all depend on what you feel like offering and who you’re offering to. Gods and spirits are very much like human people; they all have their favorite flavors, favorite ingredients, and favorite dishes. Some may be picky eaters while others are not. But like most people, none of them are going to be upset about getting free food.
If you’re unsure, you can always offer water. Water is universally appreciated, and the gesture of giving water is one of our oldest and most sacred forms of reciprocity. Everything knows what it means.