Okay, this is not really panini-- it is more like a squashed grilled cheese. That has at least one advantage: grilled cheese has that tasty, buttery crust. So what there are no grill marks. This was a big hit with the family, although the caramelized onions caused some brief complaints about fumes-- I made extra onions for the cherry-onion-stuffed pork I hope to make tomorrow! Anyway, back to the sandwiches-- what a combination-- buttery, chewy rye bread, rich onions, sausages, and cheese, and tangy mustard, all smooshed and melted together. Great stuff.