Heat your oven to 200°C/Fan 180°C/Gas 6. Slice the gem squash into thick wedges. Scoop out the seeds (you can leave the skin on or peel it). Chop the tomato into thick wedges. Peel the onion and slice into wedges. Arrange all three in a large roasting tin and drizzle with 1 tbsp oil. Season and toss to coat. Roast for 25 mins, turning halfway.
While the veggies roast, tip the pearl barley into a small pan and add 150ml boiling water. Return to the boil, cover with a lid and then reduce to a gentle simmer. Cook for 20-25 mins, till the grains are tender, then tip into a sieve and rinse with cold water to cool. Shake dry and tip into a large bowl.
While the veg and barley are cooking, make the dressing. Peel and grate the garlic into a small bowl. Pick half the oregano leaves off their stalks and roughly chop them. Add to the garlic. Stir in the balsamic vinegar and 1 tbsp oil, along with a little salt and pepper, till well combined. Set aside.
Strip the kale leaves away from their tough stalks and roughly shred the leaves. When the veg has finished roasting, tip them into the bowl with the pearl barley. Toss the kale into the empty roasting tray and return to the oven for 5 mins, or till crisp round the edges. Add to the large bowl.
Spoon the oregano and balsamic dressing into the salad and fold to combine. Pile onto plates and finish with dots of the sheep’s cheese and the remaining oregano leaves.