I usually use gouda or edam cheese instead of the sharp cheddar and gruyere (we don't have those in my country). I also skip the parmesan on top. This dish is seriously one of the best things I've ever cooked. It was so darn good; I couldn't stop eating it, and my hubby loved it too. And the other day, I accidentally left it in the oven for an extra 15 minutes, but it still tasted fantastic!
