Step 1

In a large skillet, heat olive oil over medium-high heat. Add onions, celery, carrots and green pepper; cook for 4 minutes.

Step 2

Stir in garlic and cook 1 more minute.

Step 3

Remove from heat and transfer to a 6-quart slow cooker; add remaining ingredients.

Step 4

Cover and cook on low 6 hours or on high 3 hours.