Peel and cut the floury potatoes into 2 cm cubes.
Peel and chop the carrots into 1 cm pieces.
Bring a large pan of lightly salted water to the boil.
Add the potatoes and carrots and cook until just tender but still firm, about 10–15 minutes.
Add the peas for the last 2 minutes of cooking.
Drain the vegetables well, then spread them out on a baking tray to cool completely.
If using eggs, place the large eggs in a pan and cover with cold water. Bring to the boil, then simmer for 10 minutes. Drain, cool under cold running water, peel and roughly chop.
In a large bowl, combine the cooled potatoes, carrots, peas and chopped eggs (if using).
Stir in the mayonnaise until the mixture is evenly coated.
Season with salt and black pepper, then gently fold to combine.
Cover and chill for at least 1 hour or overnight.
Before serving, give the salad a final stir and adjust the seasoning if necessary.