Step 1

In a large skillet, heat olive oil to medium-high. Cook and stir garlic, onions, and bell peppers until softened, about 5 minutes.

Step 2

Combine sauteed vegetables, tomatoes, vegetable broth, salt, and red pepper flakes in Crock-Pot. Cover and cook on low for 8 hours.

Step 3

Using an immersion blender, blend soup until smooth. Serve immediately with fresh basil as a garnish.

Step 4

Top with Parmesan cheese, croutons, yogurt, or grilled cheese croutons as desired.