1. Preheat the oven to 200°C/400°F/gas 6.
2. Peel the vegetables, halving any larger ones lengthways. Break the garlic bulb into cloves, leave them unpeeled and bash them slightly with the palm of your hand. Pick the rosemary leaves.
3. Put the potatoes and carrots into a large pan of boiling salted water on a high heat and bring back to the boil. You might need to use two pans. Boil for five minutes, then add the parsnips and cook for another four minutes.
4. Drain the veggies in a colander and allow to steam dry. Take out the carrots and parsnips and put to one side.
5. Shake the colander around a little to fluff up the potatoes – it’s important to “chuff them up” like this for those “lovely crispy bits” later on.
6. Put a large roasting tray over a medium heat and either add a few generous lugs of olive oil or gently spoon a little of the fat from the meat you’re cooking. Then, add the garlic and rosemary.
7. Tip the veggies into the tray, season with a hearty pinch of sea salt and black pepper and turn the veg over to coat them in the flavours. Spread them out evenly into one layer. This bit is important as you want them to roast rather than steam.
8. Roast for one hour – or until golden and crisp – then serve immediately with your roast dinner. For the final touch, add a few lashings of tasty gravy.