1. Saute shallots and garlic in butter and add flour to make roux. Add milk, whisk to prevent lumps. Add oregano and check for lumps. (Based upon the instructions in step #2 I think you need to add the thawed & drained spinach here.)
2. Strain roasted red peppers in colander from juice and dice fine. Rinse the diced peppers and strain excess liquid, add to spinach cream.
3. Strain and quarter artichoke hearts and add to spinach cream.
4. Add Parmesan and American Cheeses to the hot spinach cream and cook until the cheeses are melted and combine with the spinach cream.