Preheat your oven to 190°C/170°C(fan)/375°F/Gas 5. Put all of the ingredients, apart from the rosemary, on a baking tray and mix well. Put in the oven for 15 minutes.
Mix the swede well, so a different side is touching the baking tray and add the chopped rosemary and put it back in the oven for 15 minutes until cooked through.
Notes
Make sure you peel the skin off well, as the skin can get really bitter when roasted. A sharp knife is essential for being able to cut the swede, without risking cutting your fingers off.
Make sure that there is enough space on the roasting tray and that the swede is just in a single layer. If it is all piled up, then it will steam rather than roast and it won't get nice and crispy. You might need to use two baking trays.
The smaller you cut the swede cubes, the quicker they will cook. So if you want quick cooking and crispy, you need to cut them up small.
Make sure you don't overcook the swede, otherwise it will lose some of the nutritional value.