Portable Butane Stove – these can be used indoors (with proper ventilation) and get plenty hot. They have combo grills too where the grill is attached to the element. The best thing to do though is to buy a separate stove and grill from the same company so that its a tight fit but you can just throw the grill pan into the sink or dishwasher later. We have this Iwatani butune stove and this Iwatani Korean BBQ grill pan and we love them. If you mix and match, sometimes the grill and the stove won’t be a good fit and the grill can slide right off. The difference between a $20 grill and a $50 grill is immense, by the way.
Pro tip: You’ll want to keep a window open during your KBBQ party no matter what grill you use because it will get smoky. If you have a backyard, you can do a backyard KBBQ party but if you don’t, you can do it at home too, just keep your hood fan on and know that you’ll need ventilation. Maybe keep a stick around to press the hush button on your smoke detector if you have crazy tall ceilings.