include external html file and pass in variables

Question

include external html file and pass in variables

I saw this post on how to include an external html file and it works well.
Q: Is it possible to pass in variables from node into the html file?
node:

var http = require('http'), fs = require('fs');

var mytitle = 'Bold Title';//<< pass this into the html markup

fs.readFile('./markup.html', function (err, html) {
    if (err) {
            throw err; 
    } 
    exports.serve = function(req, res) {
        res.writeHead(200, {'Content-Type': 'text/html'})
        res.write(html);  
        res.end(); 
    };      

});

html:

<!DOCTYPE HTML>
<html lang="en-US">
<head></head>
<body>
    <p> [mytitle] </p>
</body>
</html>

The reason: the html markup will be quite large and if i pass the entire dom as a variable it gets messy and difficult to read.
Is there a better way to do this?

function page(req, res, pre, cb) {

    var mytitle = 'Bold Title';

    var content = '<html>\
    <head></head>\
    <body>\
    <p>'+mytitle+'</p>\
    </body>\
    </html>';

    res.writeHead(200, {'Content-Type': 'text/html'})
    res.end(content);
    cb();
}

node.js