Preheat oven to 475 F. Toast walnuts in oven while it is heating, about 5 minutes, until deepened in color and fragrant. Meanwhile, cut squash in large cubes and give the onion a large chop. Mince rosemary.
Place squash on a large cookie sheet. Drizzle with 1½ tablespoons of olive oil, season with salt and pepper, and toss to coat. Toss together the onions and rosemary with the remaining 1 teaspoon of olive oil on a separate sheet. Place both in fully heated oven and toss the vegetables on the pan after 15 minutes, then continue cooking another 10 to 20 minutes until soft and browned in spots; the onions will take a shorter time. Remove both from oven and set aside.
In a small bowl, whisk together vinegar, shallot, mustard, maple syrup and olive oil, then slowly drizzle in walnut oil, whisking to thicken. Season with salt and freshly cracked pepper, taste, and adjust ingredients and seasonings as desired.
Mix squash together with the onion and rosemary mixture and spoon onto a platter. Scatter with dried cranberries and toasted walnuts. Drizzle with vinaigrette and garnish with chives. Serve on a bed of greens, if desired, and pass additional dressing around the table.
Serve warm or at room temperature.
Recipe by SAPeople South African Recipes at https://tastyrecipes.staging.sapeople.com/roasted-butternut-squash-salad/