In a large bowl, combine warm water, sugar, and yeast. Stir gently and let stand for 5-10 minutes until the mixture becomes foamy, indicating the yeast is active.

Add the flour and salt to the yeast mixture. Mix with a spoon or your hands until a shaggy dough forms. It might seem dry at first.

Add the vegetable oil. Turn the dough out onto a lightly floured surface and knead for 8-10 minutes until it is smooth, elastic, and no longer sticky. The dough should spring back when lightly poked.

Place the kneaded dough in a lightly oiled bowl, turning it once to coat. Cover the bowl with a damp cloth or plastic wrap and let it rise in a warm place for 1.5 to 2 hours, or until it has doubled in size.

Once risen, gently punch down the dough to release the air. Transfer it back to a lightly floured surface and roll it into a long cylinder.

Divide the dough cylinder into 12-16 equal pieces, depending on your desired bun size. Keep the unused portions covered to prevent drying.

Take one piece of dough and flatten it with your palm. Using a rolling pin, roll it into a round wrapper, about 3-4 inches (7-10 cm) in diameter, making the edges slightly thinner than the center.

Place about 1-2 tablespoons of your desired filling (not included in this recipe) in the center of the wrapper. Don't overfill.

Pleat and gather the edges of the dough to enclose the filling, twisting gently to seal at the top. Alternatively, you can simply pinch the edges together to form a crescent or half-moon shape.

Place each formed bun on a small square of parchment paper to prevent sticking. Arrange the buns in a steamer basket, ensuring there is at least 1 inch (2.5 cm) of space between each bun.

Cover the steamer basket and let the buns rest for a second proof for another 15-20 minutes. They should look slightly puffed.

Bring water to a boil in the bottom part of your steamer. Once boiling, place the steamer basket with the buns over the boiling water.

Steam the buns over medium-high heat for 15-20 minutes, depending on their size and filling, until they are cooked through and visibly fluffy. Do not open the lid during steaming. After steaming, turn off the heat and let the buns rest in the steamer for 2-3 minutes before opening the lid to prevent them from deflating.

Serve the homemade Chinese steamed buns hot and enjoy your delicious creation!