Mix together the mince, fish paste, pepper, salt, water, sesame oil, fish sauce and chicken bouillon powder in a bowl, then set aside for later.
To prepare the tomatoes, cut them in half along the width and gently squeeze each piece to remove any excess liquid. Then use a teaspoon to scoop out the seeds and lay them open side down in a colander.Note: This step will reduce the amount of water in the tomatoes. If there is too much liquid, the filling may not stick as easily. For the eggplants, you will need to cut them into segments so the meat can be sandwiched in between. To do so, make a cut about 1cm (0.4") from the tip that goes halfway through the eggplant. Repeat the cut another 1cm (0.4") in from the first incision but slice it all the way to break the piece off. What you'll end up with is a piece of eggplant that can be opened in the middle like a mouth for the filling. When preparing the tofu, make an incision in its center about 3cm (1.2") long and 1cm (0.4") deep to act as a pocket for the mince.Note: Every tofu brand will make their tofu differently, so just make the cut big enough for the stuffing without breaking anything.
Slice the bittermelon into 1.5cm (0.6") thick slices, then use a small thin knife to remove the center. Simply cut around the softer paler flesh and push the middle out to create a hole for the filling.
Finally, run a knife from the top of the chili to the bottom until it can be opened. Use a teaspoon to scoop out the seeds.
To stuff all of the ingredients, use the back of a teaspoon to scoop the meat mixture. Then wedge it between the slits or gaps and smooth it out. Note: The amount of filling you use is entirely up to personal preference, but we like to use less so it cooks faster. Fill a wok or pan up with enough oil to cover the base, then pan fry the Stuffed Tofu ingredients on medium heat until the filling is golden brown. Cooking times will vary depending on vegetable, but you're looking at roughly 10-15 minutes per batch.Refill the oil as the vegetables absorb it.Tip: Put the mince side down first so it cooks through before flipping.
Meanwhile, combine the water, chicken powder, sugar, light soy sauce and oyster sauce in a pot over medium heat and bring it to a gentle simmer.
Mix the potato starch with 1 tbsp water and slowly pour it in while stirring the sauce.
Serve the sauce with the Stuffed Tofu immediately while still hot!