Heat your oven to 180°C/Fan 160°C/Gas 4. Zest and juice the orange into a bowl. Peel and crush 1 garlic clove. Add to the orange. Sprinkle in 2 tsp dried oregano, 1 tbsp oil and some seasoning. Stir together.
Add the pork strips to the orange dressing. Turn to coat the pork, then set aside to marinate.
Scrub and slice the sweet potatoes into thin rounds (no need to peel them). Cut the aubergine into 1cm-thick rounds. Peel and chop the onion into chunky wedges. Tumble the veg into a large roasting tin with the cherry tomatoes.
Crush the other garlic clove. Whisk in a mug with 1 tbsp oil and some salt and pepper. Pour over the veg and toss together. Roast for 20 mins. Stir the veg to turn them over. Roast for another 10 mins till tender.
Crumble half the pack of feta over the veg. Scatter over the sage leaves. Put the tin back into to the oven and cook for 10 mins to melt the feta.
Warm a frying pan over a medium heat. Tip in the pork (keep the marinade). Cook and stir for 5 mins till the pork is browned. Add the marinade and bubble for 3 mins. Serve with the roast veg.