Heat oil in a saucepan over medium heat.
Add flour and whisk until well combined, about 1 minute.
Add remaining ingredients except salt and pepper, whisk, bring to boil, then reduce to simmer.
Simmer for 10 minutes or so, until thickened, whisking occasionally.
Season with salt and pepper.
This can be stored for up to 1 week in the refrigerator in an airtight container. It also freezes well.
