Start by washing and thoroughly drying your baby spinach. Place the leaves in a large, wide serving bowl and scatter the thinly sliced red onions over the top to distribute their sharp flavor evenly.
In a small glass jar or a mixing bowl, combine the extra virgin olive oil, apple cider vinegar, honey, Dijon mustard, salt, and black pepper. Whisk vigorously or shake the jar until the ingredients are fully emulsified and the dressing looks smooth and slightly thickened.
Evenly sprinkle the dried cranberries, crumbled feta cheese, and chopped walnuts over the bed of spinach. These toppings provide the beautiful red and white contrast that makes the dish look so festive for a Christmas gathering.
Drizzle the prepared dressing over the salad right before you are ready to serve it. Use salad tongs to gently toss everything together, ensuring the spinach leaves are lightly and evenly coated with the vinaigrette.
