The suggestion
Add some sort of fryer that can combine a new breading item with some existing food items to create fried forms, such as

• Fried onions from onion slices
• Fried chicken fillet from chicken fillets
• Battered Cod from cod fillets
• Chicken fried steak from steak

Frying sandwich ingredients would provide a boost in hunger and/or saturation restored.

Why this should be in the mod
Sandwichable, as I interpret it, has an emphasis placed on allowing creative freedom with the sandwiches one creates. Sandwiches and burgers with such ingredients as the ones above are pretty common, and players may like being able to create something they're familiar with.~
This would also add another crafting mechanic to make sandwich-making more engaging with more variety in ingredient processing.~