Crockpot Minestrone

My sis has this recipe on her blog, and we'll definitely be making it again!

Serves: 4 (2 cups each)
Ingredients:
1 medium zucchini, cut lengthwise in half, then cut crosswise into 1-inch pieces
2 medium carrots, cut into 1/4-inch slices (1 cup)
1 cup frozen peas****
****(can easily substitute 2 cups frozen mixed veggies for peas & carrots)
1/3 cup chopped onion
1 can corn, drained
4 cups water
1 jar (25 1/2 ounces) marinara sauce
1 can (15 to 16 ounces) kidney beans, rinsed and drained
2 cups fresh, chopped spinach or 1 box defrosted frozen chopped spinach, squeezed dry
1 1/2 cups uncooked rotini pasta (4 1/2 ounces)
1 teaspon sugar
1 teaspoon salt
1/4 teaspoon pepper & shake of crushed red pepper
shredded Parmesan cheese, if desired

Preparation:
1. Mix squash, carrots, peas, onion, corn, water, marinara sauce and beans in 3 1/2 to 6 quart slow cooker.
2. Cover and cook on low heat setting 7 to 9 hours (or high heat setting 3 1/2 to 4 1/2 hours) or until vegetables are tender.
3. Stir in spinach, pasta, sugar, salt and pepper.
4. Cover and cook on high heat setting 15 to 20 minutes or until pasta is tender. Sprinkle each serving with cheese, if desired.