Masking long merge field URL in email templates

Hi all, I'd like to mask a long URL in an email template ("Click here to approve" linking to the approval link), but it's a merge field. There are two merge fields where this is the issue- one is Case Link which is a formula field =HYPERLINK($Setup.SignersEmail_Address__c.ProdUrl__c&CaseSafeId__c, 'Case Link') The other is {!ApprovalRequest.Internal_URL}

Is this possible? How do I hide the long link in my templates? Thanks!