Step 1

Slice pork belly into long strips about ½" thick, then thinly slice strips crosswise. Heat a small pot over medium. Add pork belly and cook, stirring often, until some fat has cooked out into the pan and meat is cooked through but not browned, about 3 minutes. Pour off all but 1 Tbsp. fat (if needed). Add onion and cook, stirring often, until translucent, about 5 minutes. Add kimchi and juices and cook, stirring occasionally, until liquid evaporates and kimchi is softened, about 5 minutes.

Step 2

Add gochugaru, gochujang, and 2 cups water and bring to a simmer over medium-high. Reduce heat to medium and cook, stirring occasionally, until kimchi is very tender and flavors in stew come together, 20–30 minutes.

Step 3

Add tofu to stew and cook until heated through, about 3 minutes. Divide stew among bowls and top with scallions. Serve with rice alongside.

Step 4

Do Ahead: Stew can be made 4 days ahead. Let cool; cover and chill.