Begin by preparing the chili oil. Set a wok or small saucepan over low heat and pour in half of the oil. Add the sliced fresh Thai bird chilies and the chopped dried red chilies. Stir occasionally, allowing the peppers to slowly release their color and aroma, about 5 minutes. They should turn a deeper shade and smell fragrant but must not darken to the point of burning. Once the oil is infused and lightly tinted red, remove the pan from the heat and set the chili mixture aside.

Return the wok to the stove and add the remaining half of the oil over medium heat. Add the minced ginger and let it gently sizzle for about 1 minute to soften and perfume the oil. Stir in the minced garlic and cook for another minute until it becomes fragrant but not browned.

Increase the heat to high and add the ground pork. Use a spatula to break the meat into small crumbles, spreading it out so it sears rather than steams. Fry until the pork is no longer pink and some bits begin to turn lightly golden, developing a savory, roasted flavor.

Sprinkle in the ground Sichuan peppercorns, keeping back the reserved 1/4 teaspoon for later. Stir-fry for 15–30 seconds so the spice blooms in the hot oil, taking care not to let it scorch, which would make it taste bitter.

Add the spicy bean sauce to the wok and mix thoroughly so every piece of pork is coated in the deep red paste. Pour in the chicken broth (or water) and stir to combine, scraping up any flavorful bits stuck to the bottom of the wok. Bring the mixture to a gentle simmer and let it cook for about a minute to meld the flavors.

While the sauce is simmering, place the cornstarch in a small bowl and whisk it together with the 1/4 cup water until completely smooth with no lumps. This slurry will help thicken the sauce.

Stir the cornstarch mixture into the simmering sauce. Allow it to bubble for a short time until the liquid turns glossy and slightly thickened, coating the back of a spoon. If the sauce becomes too dense, add a small splash of extra broth or water to adjust it to a silky, pourable consistency.

Pour in the reserved chili oil along with the cooked chilies. If using a homemade chili oil that is already seasoned and salted, use only the clear surface oil so the dish does not become overly salty. Stir to evenly distribute the infused oil through the sauce.

Gently add the tofu cubes to the wok. Use your spatula to carefully lift and turn the tofu, or simply spoon the sauce over the cubes, taking care not to break them. Let the tofu simmer in the sauce over medium heat for 3–5 minutes so it warms through and absorbs the spicy, numbing flavors.

Finish by adding the sesame oil and sugar, if using, to round out the taste with a subtle nuttiness and a hint of sweetness. Sprinkle in the chopped scallion and fold it through the tofu just until the green pieces soften slightly.

Transfer the MaPo Tofu to a serving dish. Dust the top with the reserved 1/4 teaspoon of ground Sichuan peppercorn for a final aromatic, tingling kick, if desired, and serve hot with steamed rice.