Add onion to pan; saut 3 minutes or until softened.
Add oregano and garlic; saut 1 minute. Stir in squash, zucchini, carrot, and corn; saut 5 minutes or until vegetables are tender.
Remove from heat.
Place 3 cups tomato and 1 can broth in a blender; process until smooth.
Add tomato mixture to pan; return pan to heat. Stir in remaining 1 cup tomato and remaining 2 cans broth; bring mixture to a boil. Reduce heat, and simmer 20 minutes.
Add pasta and beans to pan; cook 10 minutes or until pasta is tender, stirring occasionally.
Remove from heat. Stir in spinach, salt, and 1/2 teaspoon pepper. Ladle soup into individual bowls; top with cheese.
Garnish with coarsely ground black pepper, if desired.