Miso Veggie Noodle Soup

Name: Miso Veggie Noodle Soup
Ingredients: 1 tablespoon olive oil; 1 onion (chopped); 2 medium carrots (peeled and chopped); 4 ounces baby bella mushrooms (sliced); 3 cups bite-sized broccoli florets; 4 cloves garlic (minced); 1 1-inch piece fresh ginger, grated; 5 ½ cups water; 5 tablespoons white miso paste; 1 5 ounce bag fresh baby spinach leaves; 4 to 8 ounces udon noodles (cooked according to package directions, drained and rinsed well); Lime wedges and red pepper flakes (for serving)