Step 1

Heat olive oil and butter over medium-high heat in a 6 quart Dutch oven or stockpot.

Step 2

Add onions, carrots, celery, and parsley to the heated oil; cook for 5 minutes, or until just tender.

Step 3

Stir in garlic and cook for 30 seconds more.

Step 4

Add vegetable broth; stir in salt, pepper, dried oregano and bay leaf.

Step 5

Bring to a boil; reduce heat to a simmer and cook for 5 minutes.

Step 6

Stir in beans and corn kernels; continue to cook for 5 minutes. Taste for salt and pepper; adjust accordingly.

Step 7

Add spinach and cook for 1 minute.

Step 8

Remove from heat.

Step 9

Ladle soup into bowls; sprinkle with parmesan cheese and serve with toasted bread slices.