I made this for supper last night with a bag of swiss chard grown by my cousin Jo. Posting the pics on Instagram has obviously whetted a few appetites so here's the recipe. A savoury souffle is not as hard as it looks and can turn very economical ingredients into a luxurious dish. For a perfectly fluffy and towering souffle, remember no peeking while it's cooking. Put it in the oven (don't slam the door or you'll knock the air out) and patiently wait for the cooking time to elapse. Experiment by using different cheeses and swap spinach for mushrooms, cooked leeks, roasted peppers or anything else you fancy.