Go into local multiplayer
Start up two additional controllers then press a button to join and make ready
Press a button to continue
On match settings go to the word default and press a to change to custom.
In the enemies section I turned them all to off. I also changed enemies to low, though that probably doesn't matter.
Once starting the game, move controllers to have chefs under bun, then walked on the bun with my chef.
Alternately, you could go online and play against two others and hit them with part of the burger.