Bring a large pot of salted water to a boil and cook the pasta according to package instructions until al dente, about 8–10 minutes. Reserve 1 cup of pasta water, then drain the remaining water and set the pasta aside.

In a large skillet over medium-high heat, cook diced pork belly until crispy and golden brown, about 5–7 minutes. Remove from pan, leaving drippings.

Return the skillet to medium heat, add reserved pasta water and ssamjang, whisk until smooth and creamy. Simmer for 2–3 minutes.

Add drained pasta and crispy pork belly into the skillet, toss gently to coat with sauce for about 2 minutes.

Remove from heat, stir in parmesan cheese and beaten egg until creamy. Serve topped with green onions.