What is wrong with my code in answer to the following question & error?

Question: The message in the final echo command only makes sense if your favorite flavor is the same as Hal's. Add a conditional around that final echo command that checks if the flavor variable has a value of "cookie dough." (Remember to choose carefully between using a single equal sign and a double equal sign in the check.) Preview the code and, if you have a different flavor, make sure the message disappears.

Error: I do not see the flavors set properly.

<?php
$flavor = "vanilla";

echo "<p>Your favorite flavor of ice cream is ";
echo $flavor;
echo ".</p>";
if($flavor == "cookie dough") {
  echo "<p>Hal's favorite flavor is cookie dough, also!</p>";
}

?>