I can't make it to the event, but I do have some ideas if someone is willing to try them out:
Deconstructed Slider Mac & Cheese1. Separate out the meat, buns, onions, and pickles.
2. Saute the onions with garlic & crushed red pepper, and incorporate it into the cheese sauce. If you got cheeseburgers, use the cheese from the burgers in the cheese sauce.
3. Cube the meat and stir it in with the pasta.
4. Pour the mac & cheese into a casserole pan.
5. Toast the buns, and grind them into breadcrumbs
6. Stir half of the breadcrumbs in with melted butter, and use it to encrust the top of the casserole.
7. Coat the pickle with the leftover breadcrumbs, and fry them.
8. Bake the mac & cheese mixture in the casserole pan until the crust is golden.
9. Garnish with the fried pickles.
White Castle French Onion Soup1. Gently reduce the onions for several hours until caramelized.
2. Coarsely grind the meat patties in a food processor.
3. Simmer the ground meat patties in water.
4. Strain the "broth", and reduce until it reaches a sufficient strength.
5. Combine the "broth" with the caramelized onions in ramekins.
6. Toast and trim the buns to use as the crouton.
7. Cover the crouton with cheese (preferably from the burger).
8. Set under the broiler until you've either got (a) French Onion Soup, or (b) the whole thing catches fire and you can toss it.
The soup is a bigger reach because I have no idea whether you can actually reconstitute a broth from cooked meat. I'm hopeful because it's steamed instead of grilled, but... yikes. That's a big risk relative to the mac & cheese (which I'm pretty sure will work).
"I've always thought pastrami was the most sensuous of the salted cured meats."