Here's how I make mine...it's easy, low-calorie and delicious.
Cut round steak into serving sized pieces and put in sprayed baking dish. Slice onions thinly and put over the top. Season with salt & pepper, and a little garlic/herb seasoning if you wish. Sprinkle a tablespoon or so of flour over the top, pour a small can of tomato sauce over all, cover with foil and bake in a 350 oven for about an hour.
I also add quartered potatoes and baby carrots, which I know your wife can't have, but you could substitute cabbage wedges, chunks of zucchini, brussels sprouts, etc.
We get by with a little help from our friends