Cook guanciale in a cold pan set over low-medium heat until crispy and the fat has rendered. Remove guanciale from pan and reserve the hot oil.
Boil tteokbokki until it's almost cooked and drain. Reserve 1 cup of the cooking water.
Whisk together eggs, cheese and black pepper. Add 2 Tbsp reserved guanciale oil and ½ cup warm cooking water and whisk to temper the eggs.
Add tteokbokki to the pan set over low heat, then pour in the egg mixture and stir/toss until a glossy, smooth sauce forms, adding more water if needed.
Toss through half the guanciale and divide into bowls. Serve with extra guanciale and extra sauce over the top. Devour immediately.
