Using the roll-cut method, slice eggplant into larger than bite-sized pieces. Transfer to a large bowl and rub about ½ teaspoon salt all over the eggplant. Set aside for 5-10 minutes.
You may or may not get a lot of moisture at this point. If you do, drain it out but reserve some so the flour can blend in and stick to the eggplant.
Lightly coat the eggplant with 2 tablespoons of flour.
Heat a large wok with enough oil for frying (the height of the oil should cover the eggplant) to about 350F. Carefully drop the coated eggplant into the hot oil.
Using a pair of chopsticks, move the eggplant around so they cook evenly.
Flash fry for about 1 - 2 minutes until a thin crust is formed. Using a sieve, remove eggplant and drain on a towel to absorb excess oil.
Clean the wok or pan and set it over medium heat. Add a drizzle of oil and sauté garlic until aromatic. Then, continue to stir-fry the peppers and onion for another minute until as crisp as you like.
Add the doubanjiang, stir to combine.
Add the eggplant and remaining sauces, then quickly toss everything together to combine. If it appears to be too dry, add about 3-4 tablespoons of water then continue to stir-fry until flavors meld. Taste test and season with more doubanjiang or soy sauce.
Doubanjiang - the link above comes in 3 bottles, and it's always more cost saving to get this one at the store. There are other brands that you can use, such as LeeKumKee or those that labeled hot bean sauce (spicy).