01 - Set oven temperature to 400°F.
02 - Individually wrap each beet in aluminum foil, place on a baking sheet, and roast for 40 to 50 minutes until tender when pierced with a knife.
03 - Remove beets from foil, allow to cool until touchable, peel, and cut into wedges or bite-sized cubes.
04 - In a small bowl, whisk together olive oil, balsamic vinegar, Dijon mustard, honey, salt, and pepper until emulsified.
05 - Combine arugula, roasted beets, and sliced red onion in a large bowl. Drizzle with dressing and toss gently to evenly coat.
06 - Transfer salad to a serving platter, then sprinkle with crumbled feta and toasted walnuts.
07 - Serve immediately to ensure freshness and optimal texture.