Step 1

Add tomatoes, tomato sauce, and next 7 ingredients (through broth) to a slow cooker/crockpot.

Step 2

Cover and cook for 2 hours on high or 4-8 hours on low.

Step 3

About 30-40 minutes before serving transfer soup to a blender or food processor and puree until smooth, then return to crock-pot.

Step 4

Prepare the roux. Begin by melting the butter in a medium saucepan over medium heat.

Step 5

Add flour to melted butter and stir until flour clumps up. Slowly whisk in the heavy cream (or half & half) until mixture is thickened and smooth.

Step 6

Add roux and Parmesan cheese to crockpot and stir to combine.

Step 7

Allow to cook another 20-30 minutes until cheese is completely melted. Give it a good stir before serving.

Step 8

Top with additional basil and parmesan cheese if desired.