01 - Preheat the oven to 375°F. Line a small baking sheet with parchment paper.
02 - Toss fresh raspberries with honey and olive oil until evenly coated. Spread on one half of the prepared baking sheet in a single layer.
03 - In a small bowl, combine chopped walnuts, maple syrup, and a pinch of sea salt. Toss to coat evenly, then spread on the remaining half of the baking sheet.
04 - Roast for 8 to 10 minutes, until raspberries are softened and walnuts are golden and fragrant. Remove from oven and let cool slightly.
05 - In a small bowl, whisk together extra virgin olive oil, balsamic vinegar, Dijon mustard, honey, salt, and black pepper until emulsified.
06 - In a large salad bowl, combine baby spinach, sliced red onion, cucumber, and crumbled feta cheese if using.
07 - Gently fold roasted raspberries and walnut crumble into the salad base.
08 - Drizzle with balsamic dressing just before serving and toss lightly to coat evenly. Serve immediately.