Convert string into HTML tags

Okay I know there has to be a simple way to do this but everything I've tried is working backwards. I am attempting to add subheadings to my sorted tables using a <td colspan=x class='subheader'> approach. However, I cannot for the life of me get the Laravel {{}} function to output text that a browser will properly interpret.

Here is my function:

function catTable($record,$nCols)
{
  if(session()->has('seafood_category')) //IF WE'VE ALREADY SET IT, WE NEED TO CHECK IT
  {
    if (session()->get('seafood_category') == $record->seafoodCategory->category)  //IF THE CATEGORIES ARE THE SAME
    {
      return ''; //NOTHING TO DO HERE
    }
  }
  $cat=$record->seafoodCategory->category;
  $html="<tr>
          <td colspan='$nCols' class='subheader'>
            $cat
          </td>
        </tr>";
  session()->set('seafood_category',$cat);
  return $html;
}

I've included this in a @foreach() loop in building my table and I'd like to insert the table row when the event is triggered. I know I must be missing something totally basic but I can't for the life of me find it. Any help would be greatly appreciated, thanks.