Fillet of sole with piquant tomato sauce

1/3 c. thinly sliced yellow onion
2 1/2 Tbsp olive oil
3/4 tsp finely chopped garlic
1/2 tsp oregano
1 Tbsp capers (this are available in a jar, generally in the same
   section of the store as olives and pickles, a small jar will last
   you a long time)
1/2 c. canned chopped tomatoes and their juice
Salt to taste
Black pepper
1 lb. fresh sole fillets

1. Saute onion in olive oil until soft and pale gold in color.  Add
garlic and saute until it just starts to turn yellow/light brown.
Stir in the oregano and capers.  Add tomatoes with juice, salt and
pepper.  Stir and simmer for 15-20 minutes.
2. Rise and dry fish fillets.  Smear bottom of baking dish with a
little of the tomato sauce (approx. 1 Tbsp).  Dip each fish fillet in
the sauce, then arrange in baking dish so that fillets are just
slightly overlapping.  Pour remaining sauce over fish.  Bake in 450
degree oven for no more than 5-8 minutes (depending on thickness of
fish).
3. If sauce thins during baking (because fish gives off liquid in
cooking process), pour sauce back into pan and boil rapidly until
thickened before pouring over fish and serving.