Cut the bacon in to thin slices and finely slice the onions. Warm a small skillet over a medium heat and add the bacon.

After a couple of minutes, it should start to render some fat. At this point, add the onions. Continue to cook, stirring now and then, until the bacon is starting to crisp and the onions are turning a caramelized brown. This will take probably 25min or so. Don't let them burn - reduce the heat if you need to and if you are short on fat, add a little but there should be enough from the bacon.

Once the onions are nicely brown, add the spaetzle and cook another minute or two. Add the cheese, mix through, then serve with the chives sprinkled on top.