Make the Sauce: Combine miso, sugar, mirin, soy sauce, and Tobanjyan in a bowl. Stir until smooth and set aside for later use.
Cook the Eggplant: Heat oil in a skillet over medium heat. Add the eggplant pieces, cooking until they're tender and slightly browned. Once cooked, transfer the eggplant to a plate and set aside.
Prepare the Pork: In the same skillet, add the pork belly pieces. Stir-fry until the pork is cooked through and begins to crisp on the edges.
Combine Ingredients: Reintroduce the eggplant to the skillet once the pork is cooked. Pour the sauce over the pork and eggplant, stirring well to coat everything evenly. Let the mixture simmer for a few minutes, letting the flavors meld together.
Finishing Touches: After the sauce has thickened and the ingredients are well combined, remove the skillet from the heat. The dish is now ready to be served.
