Can this recipe be doubled? If so, does the baking time increase?

Sure, you can double the recipe. You just need a second baking sheet to contain it, so you keep it all in a single layer- unless you own a really large baking sheet that can do the job. The baking time won't increase really, especially if you are using two separate sheets. Each one bakes independently of the other, and they aren't "stealing" oven heat from one another. You might want to rotate the sheets midway through the baking time for even baking, but you really ought to do that even if you are only making one recipe worth.