Place Group 1 in saucepan and bring to a rolling boil until vegetables are tender. Replace liquid lost during cooking process. Bring back to heat. Add Group 2 and mix together. Mix Group 3 into a slurry and add to vegetables. Cook through for a further 2-3 minutes. Cool filling down then place in refrigerator until required.
Do not leave prepared Vegetable Filling on bench uncovered during the cool down process.