"What the heck is going on in that picture?"
I can get past the fact that the skillet is about 1/3 the size that it needs to be for the amount of food in it. This is disaster and heartache waiting to happen if one thinks they are going to try and cook this amount of food on the stove top, but for the moment we will assume that the intent is to put the skillet into the oven. Slide it in there at 375 and let the chopped onions and celery cook in the hamburger juice that runs off - could work.
But wait, it's already garnished. This is the final dish, ready to be served. Either mom has gone insane, or she's turned into an evil gourmet. "Grab your sporks kids, it's hamburger tartare on a bed of raw shallots and celery." Mmm. A bit of vanilla and ground turmeric and you're set. It's best if the centre is still slightly frozen.