Combine sugar and instant yeast with 1 cup of warm plant-based milk or water. Let sit for about 10 minutes until foamy.

In a separate bowl, whisk together flour and salt. Pour in the yeast mixture and 2 tablespoons of oil. Knead until soft and elastic, about 5 minutes.

Cover the bowl and let the dough proof in a warm place for about 30 minutes or until it doubles in size.

Shred zucchini and sprinkle with salt; let it sit for 30 minutes to draw out moisture.

Sauté sliced mushrooms in a skillet over medium heat until fragrant and browned, about 5 minutes.

Combine drained zucchini with sautéed mushrooms, grated carrot, and chopped scallions. Season with soy sauce, toasted sesame oil, white pepper, and salt. Mix well.

Once dough has doubled, punch it down and divide into 14 equal portions. Shape each portion into a smooth ball and flatten into 3-inch wrappers.

Place a spoonful of filling in the center of each wrapper. Pleat the dough edges to seal the filling, pinching to create a secure closure.

Heat a non-stick frying pan over medium-high heat and add 2 tablespoons of oil. Fry buns for 4-5 minutes until the bottoms are golden and crispy.

Add enough water to cover the buns by 1-2 centimeters. Cover with a lid and cook for 6-8 minutes until water evaporates and buns are cooked through.

Remove the lid and crisp the buns for another minute. Transfer to a plate and garnish with sliced scallions or toasted sesame seeds. Serve hot with soy sauce or chili oil.