I didn't alter the method at all, so head on over to http://naturallyella.com/2013/07/03/roasted-beet-and-blue-cheese-frittata/ for directions. The only thing I'd add is that we don't have a cast iron skillet so I used a large frying pan. Our current pan has a metal handle but our previous one had a plastic one and I used to often put it in the oven without any problems.

We had our frittata with boiled new potatoes and steamed cauliflower from the same harvest as the beetroot; it made for a really tasty and completely seasonal locally-sourced meal.