Bring a pot of water to boil while you preheat the oven to 400 F. Simmer the potatoes and carrots for 5 minutes, then add the parsnips and cook another 4-5 minutes.
The squash doesn't need to be parboiled.
Drain in a colander and let sit for a few minutes. Take everything but the potatoes out of the colander then shake the colander around a bit to shake up the potatoes.
Put the vegetables in a shallow pan, along with a few cloves of garlic and some sprigs of fresh parsley if you have some. (Grow some! ) Drizzle some olive oil and add salt and pepper to taste. Sprinkle some paprika on the squash if you'd like.
Roast at 400 for 45 minutes to an hour, depending on the size of the vegetables.