If you have an oven, preheat it to 220C (425 F).
Find a non-stick frying pan with a cooking surface about the size of your hands (reference video). It should also have walls that are at least a few inches (2 inches) in height. Put some oil in the frying pan and place on a medium heat.
Once hot, place in bacon and bratwurst. Cook the bratwurst pieces until you get some browning on the edges. Then add in the potatoes and onion pieces. Once the potato get some browning on the edges, add in the kimchi. Stir-fry everything until the kimchi start to wilt and get some browning on them as well.
Then move the stir-fried ingredients from the frying pan to a plate. Give your frying pan a quick wash to get rid of the burnt Kimchi residue. Put the clean frying pan back on the stove. Place on a medium-low heat this time. Put it some oil and wait until it gets hot.
Once hot, place the stir-fried mix back in. Then slowly pour in the beaten eggs in a circular motion around the pan. Move the pan around so you get all of the stir-fry evenly coated. Put a lid on the frying pan and let it cook for 1 minute.
After 1 minute, take off the lid and use your spatula to slide around the edge. This will keep the edges from sticking to the frying pan.
Now, if you have a oven, stick it in the hot oven (without the lid) for a few minutes. Take out when the top of the frittata is fully cooked through.
If you do not have an oven, place your stove-top to a low heat. Put the lid back on and let it cook on the low heat for 6-8 minutes. Keep an eye on it and turn off the heat when the top of the frittata is fully cooked through.