Heat up a wok or saute pan at medium-high heat, add 1 tbsp vegetable oil and add the onion. Cook for 2 minutes, then add the remaining ingredients except for spring roll wrappers and the hoisin dip. Cook for 5 minutes stirring occasionally. Turn off the heat once vegetables are tender, but a little crunchy. If you prefer softer vegetables, cook for a few minutes more.
To wrap your spring rolls, place the wrapper in a baking sheet with hot water until soft for 10-15 sec.
Remove wrapper and pat blot on a damp tea towel.
Place filling in the middle of the wrapper.
Fold over the bottom and sides and roll wrapper upwards to form a neat roll shape.
Add plenty of vegetable oil to the wok (cleaned and dried) and once hot, add the spring rolls and fry for about 1 minute or until golden brown, flip occasionally so it browns evenly.
Place it on a plate with paper towels to remove excess oil.
Make the hoisin dip
Mix all ingredients apart from water in a medium sized bowl. If the dip becomes too thick, add more or less water to reach the consistency you prefer by adding a spoonful at a time. Adjust seasoning if needed.
Notes
Nutrition calculations assume spring rolls drain after frying.