Group by month/Year only using a date field

Summary

How can I group by month/year only using a date field from Sales Cloud?

Content

I have a report which includes a date field from Sales Cloud Opportunity object. I would like to group this report by the month/year element only.

I tried to add a month only field in Sales Cloud, which could then be brought through to the report and used for grouping, but the only date fields available are the full date format.

Is there any way in reporting that I can group by the month/year element only on a report?

I would appreciate any help or suggestions, thank you.