Bring a large pot of water to a boil and cook your udon noodles just for a minute or so until they come apart. Drain and set aside.
While your udon noodles are cooking. Cook your chopped bacon over low heat. Once finished add in your kimchi and your gochujang and stir for a bit letting cook for a few minutes. Pour in your water and reserved kimchi liquid and bring to a simmer and let cook for a few minutes.
Toss in your udon noodles and turn to coat with the sauce. Add in your butter and toss to combine.
Serve in bowls with an egg yolk on top and sliced green onions, nori and sesame seeds to garnish.
