Grouping by Week Starting Date

[Randyr]

Hello, I am a new Power BI user.  I am looking at Salesforce Live Chat Transcript cases and I am trying to count how many cases were created by week.

I have been able to do this by creating a new Column   Week = WEEKNUM('Live Chat Transcript'[StartTime])

And this new Measure - WeekGroup = CALCULATE(Count('Live Chat Transcript'[CaseId]), ALLEXCEPT('Live Chat Transcript','Live Chat Transcript'[Week]))

This shows me the information by Week 1, Week2, etc. However I want to be able to show  Week Starting ...Jan 1, Jan 8, Jan 15, etc.    

I appreciate any assistance you can provide on how I can do this.

Thanks