Easy Creamy Spinach Soup

Name: Easy Creamy Spinach Soup
Prep time: 10 min
Cook time: 25 min
Total time: 35 min
Cuisine: American
Ingredients: 2 teaspoons olive oil; 2 cloves garlic (minced); 1/2 medium onion (finely chopped); 1 stalk celery (finely chopped); 1 medium potato (peeled and cubed); 2 cups chicken or vegetable broth; 2 cups fat-free milk; 1 (6-ounce) bag baby spinach (divided); Black pepper (freshly ground to taste); Kosher salt (to taste)