Did you have Meatloaf served on a bed of lettuce?

No

Are you sure you didn't have a bunless burger

What is the traditional Festivus meal?

Here's How To Make A Traditional Festivus Meal
The traditional Festivus meal, as seen on Seinfeld, is meatloaf on a bed of lettuce, with simple sides like peas or mashed potatoes, reflecting its low-budget, humble origins for "the rest of us".