Place the carrots in a pot and cover with a generous amount of cold water. Boil until just tender, but still a little firm. When there, add the cauliflower, snap peas and bell pepper and cook 3 minutes more. Drain well and cool the vegetables in ice-cold water, and drain well again. Store the vegetables in a bowl in the fridge until ready to reheat.
To heat, place the butter, stock and garlic in a very large skillet and bring to a simmer. Add the vegetables and heat through. Season with salt and pepper, sprinkle with parsley and serve.