Can I get the weekday from a date in an email template

Can I get the weekday from a date in an email template

Hi.

I've created an email template associated with Deals, and I can use it to get information from the Deals module for example.
I would like to get the weekday for a date variable.
So, for example I have a variable ${Deals.Workshop Start Date}, and I would like to get the weekday for that date, so that the email will say, for example 'Looking forward to meeting you at the workshop on Thursday'.

How could I achieve that? Is there a global function I can access from within the email, or could I create another variable in the deal based on the Workshop Start Date variable?

Many thanks.

Gavin