Peel and slice the nagaimo into 1cm half-moon shapes. Slice the tofu into 1cm pieces. Mince garlic, ginger, and half of the green onion.

Place Sichuan peppercorns in a plastic bag and crush lightly with a rolling pin.

Heat sesame oil in a pan and sauté garlic, ginger, and half of the green onion. Add doubanjiang and stir until fragrant.

Add ground meat and crushed Sichuan peppercorns, cooking until the meat changes color. Add nagaimo slices and stir-fry further.

Pour in chicken stock and add tofu slices. Bring to a boil, then add oyster sauce, soy sauce, and the remaining green onion. Thicken with cornstarch slurry.