In a large salad bowl, combine the fresh spinach and sliced strawberries.
Add the crumbled feta cheese, toasted sliced almonds, and red onion to the bowl.
In a small mixing bowl, whisk together the olive oil, apple cider vinegar, honey, Dijon mustard, poppy seeds, and a pinch of salt and pepper until well combined.
Pour the poppyseed dressing over the salad ingredients and gently toss to coat evenly.
Serve immediately, garnishing with additional strawberries or feta if desired.