Highlight (Conditional Formatting?) same date (15th) of each month

I have a worksheet where I need to set up a conditional format that highlights the same day of each month. i,e the 15th.

In the attachment. I want the 15th of each month filled black with white font.

Any help would be very helpful.

Rosters.xlsx

Pl see the attached file.

Thanks heaps. Is there any way of doing the whole worksheet at once?

Copy B12 cell and pastespecial-formats to required range.