Add 1 tablespoon of kimchi butter (see below for kimchi butter instructions) to a skillet and heat over medium heat. Add the chicken thighs and cook, 3-4 minutes per side, until no longer pink in the middle.
Remove and set aside to cool. Once cool to the touch, slice the chicken into bite sized pieces. You can do this part in advance if you'd like.
Add another tablespoon of kimchi butter to the skillet and heat over medium-high heat.
Add the chicken and cook for 30 seconds.
Add the udon noodles and garlic and cook for 2-3 minutes. It's ok if the noodles char a touch, it adds some flavor. Just be careful they don't burn.
Add the mirin and let it cook for 1 minute, tossing often.
Add the soy sauce, bacon and sesame oil. Cook until all the liquid has evaporated (about 2-3 minutes).
Serve with a fried egg on top (optional) and garnish with green onions.
Combine all ingredients in a bowl and mix thoroughly. Store in the fridge until ready for use.
