Denny's own August 2026 allergen guide states the grills are seasoned with the vegetable oil from their fryers, which they define as including soybean, canola and cottonseed, so every griddled and fried item on the menu carries seed oil. They publish no ingredient lists at all, so the additive score here is an estimate rather than a reading.
Denny's publishes no per-item ingredient statements anywhere, so most of this rests on the one thing they do say out loud. The PLEASE NOTE block of their August 2026 Allergen Guide reads: "We season our grills with vegetable oil from our fryers and with bacon. Vegetable oil includes but is not limited to soybean, canola and cottonseed oils." That is Denny's stating that the same soybean, canola and cottonseed oil is both the fryer medium and what the griddle gets wiped with, so every griddled item - pancakes, eggs, hash browns, burgers, skillets, melts - and everything fried touches seed oil, and there is no way to order around it. The same block says the information was provided by their ingredient suppliers, which tells you components arrive made rather than built in the kitchen, though the cooking itself is to order. Additives are the weak spot: with no ingredient lists published anywhere I could only estimate, so treat that one as a hunch, not a reading.