Spanish Potatoes

I'm not really sure what makes these potatoes Spanish. But the recipe is a classic example of microwave cooking.
2 large potatoes, peeled
½ Spanish onion
½ can mushrooms
3 tbsp vegetable oil
salt and pepper to taste
Slice the onion into thin, thin slices. Slice the potatoes into think slices as well. Put both along with the mushrooms into a coverable casserole dish that will fit inside the microwave. Toss the potatoes, onion and mushrooms with the oil, salt and pepper. Cover dish with led. Microwave on high for 3 minutes. Take potatoes and stir them. Cover again and microwave on high for another 3 minutes. Continue doing this until the potatoes are cooked through.