diff --git a/lib/build.js b/lib/build.js
index e4ba67f..4f805bb 100644
--- a/lib/build.js
+++ b/lib/build.js
@@ -1,4 +1,4 @@
-var extend = require('util')._extend;
+var extend = require('extend');
 var fs     = require('fs');
 var path   = require('path');
 var rimraf = require('rimraf');
@@ -11,7 +11,7 @@ module.exports = function(data) {
   var output = '';
 
   // Extend file data with global data
-  data = extend(this.options.data, data);
+  data = extend({}, this.options.data, data);
 
   // Catch Handlebars errors, because they won't show up in the Gulp console
   try {
diff --git a/package.json b/package.json
index 7aa5864..d951280 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "chalk": "^1.1.1",
     "commander": "^2.8.1",
     "escape-html": "^1.0.3",
+    "extend": "^3.0.0",
     "front-matter": "^1.0.0",
     "glob": "^4.3.5",
     "gulp-util": "^3.0.7",