Prepare the ingredients: wash and slice the strawberries, dice the avocado, and chop the walnuts.
In a small bowl, whisk together the olive oil, apple cider vinegar, honey, and poppy seeds to create the dressing.
In a large salad bowl, add the spinach as the base, followed by strawberries, avocado, red onion, feta, and walnuts.
Drizzle the dressing over the salad, then toss gently to combine without mashing the avocado.
Season with salt and pepper to taste, then serve immediately for the freshest experience.