Pre-heat your oven to 220c / gas mark 7.
Cut the carrots and parsnips in half lengthways. If you happen to get some particularly fat parsnips, you can always chop them in half again to try get them to a more consistent size with the carrots.
500 g carrots, 500 g parsnips
In a small bowl, mix the maple syrup, olive oil and wholegrain mustard until combined.
4 tbsp maple syrup, 2 tbsp wholegrain mustard, 2 tbsp olive oil
Chuck the carrots and parsnips in a large mixing bowl, drizzle over the maple syrup mix, season generously with salt and pepper, then toss or stir to coat the veg. Alternatively, you could brush the mix onto the veg directly on a baking tray.
Put the coated veg onto a non-stick roasting tray, or use some parchment paper if you don't have non-stick. Place the tray in the oven.
After 20 minutes, turn the veg over and put in the oven for another 10 minutes.
The carrots and parsnips should be tender and nicely caramelised now, but you could give them another 5 minutes if you think they need it – every oven is a bit different!