Preheat your oven to 200°C (400°F).

Prepare the beets: Trim the ends off the scrubbed beets. If they are large, cut them into halves or quarters so they are roughly uniform in size for even roasting. Place the prepared beets in a medium-sized baking dish or on a baking sheet lined with parchment paper for easier cleanup. Drizzle with 30ml (2 tbsp) of olive oil and season with a pinch of salt and pepper. Toss to coat evenly.

Roast the beets: Cover the baking dish tightly with aluminum foil (if using a dish) or cover the baking sheet tightly with foil. Roast in the preheated oven for 45-60 minutes, or until the beets are tender when pierced with a fork. The exact time will depend on the size of your beet pieces. For a baking sheet, you might need to flip them halfway through.

Cook the barley: While the beets are roasting, rinse the barley under cold running water in a fine-mesh sieve. In a medium saucepan, combine the rinsed barley with 600ml (2.5 cups) of water or vegetable broth and a pinch of salt. Bring to a boil over medium-high heat.

Simmer the barley: Once boiling, reduce the heat to low, cover the saucepan, and simmer for 30-45 minutes, or until the barley is tender and has absorbed most of the liquid. Cooking time can vary depending on the type of barley; check the package instructions. Drain any excess liquid if necessary and set aside.

Prepare the orange segments: While the beets and barley are cooking, prepare the oranges. Using a sharp knife, carefully cut off the top and bottom of each orange. Stand an orange on one cut end and, following the curve of the fruit, slice away the peel and white pith. Once peeled, hold the orange over a bowl to catch any juices. Carefully cut along the membranes to release each segment. Squeeze any remaining juice from the membranes into the bowl.

Make the vinaigrette: In a small bowl or jar, whisk together 45ml (3 tbsp) of olive oil, the fresh lemon juice, Dijon mustard, salt, and pepper. If you collected any orange juice from segmenting, add about 1-2 tablespoons (15-30ml) of it to the vinaigrette for extra flavor.

Cool and peel the beets: Once the beets are tender, carefully remove them from the oven. Let them cool slightly until they are comfortable to handle. The skins should slip off easily. You can use paper towels or a paring knife to help remove the skins.

Cut the beets: Cut the peeled beets into bite-sized pieces, approximately 1.5-2cm (0.5-0.75 inch) cubes.

Assemble the salad: In a large serving bowl, combine the warm cooked barley, the cut roasted beets, the orange segments, thinly sliced red onion, chopped fresh parsley, and chopped fresh mint. Add the toasted nuts if using.

Dress the salad: Pour the prepared lemon-herb vinaigrette over the salad. Gently toss everything together to ensure all ingredients are evenly coated with the dressing. Taste and adjust seasoning with salt and pepper if needed.

Serve: Serve the salad immediately while still warm, or at room temperature. It is also delicious served chilled.