Step One: Mix up some polenta, spread in a pan, cut into squares, let it set up, then brown in a little olive oil - or - cut up a pre-made roll and brown.
Step Two: Start with the barest amount of olive oil, some garlic and diced onions. Saute while you wash and chop the greens (any combo will do, spinach, kale, Swiss chard, collards, even romaine).
Step Three: Add the greens to the saute and cook them to your taste.
Step Four: Spread the greens over the polenta and top with Feta cheese.