How to replace the underline set by span using a class

I have the following code:

<div id="instru_topp">
                <h3>The topping</h3>
                <p><span class="especial">Mix</span> all the -- <span>Ingredients</span>  and pour it on the top cake.
                    After bakin it, you will end up with this:</p>
            </div>

and the following style for it:

#instru_topp p span:last-child {
    text-decoration: underline;
}

So I want remove the underline in those words by a red color