This is not quite a sauce, not quite a stew. It's a piece of fish, floured and seared in olive oil, briefly stewed with seared onions, tomatoes, capers and green olives. My version adds a little anchovy and hot chile peppers. If you are wondering how it tastes, it's a lot like pasta puttanesca: salty, savory, a little sweet-sharp from the tomatoes, a little spicy from the chiles. Damn good. Have lots of good crusty bread around when you serve to get all that sauce. A red wine would be a good idea, too.
2or 3 tablespoons small capersand rinsed, preferably preserved in salt
1/2cupchopped green olives
1to 2 cups diced fresh tomatoes,seeded
Salt the fish well and dust in the semolina flour.
Heat the olive oil in a large saute pan with a lid over medium-high heat. Sear for 90 seconds on each side -- you don't want them cooked all the way just yet. Remove the fish to a plate for now.
Add the onions and saute over high heat for 2 minutes before stirring. You want a little sear on the onions, here and there. Now stir them well, add the anchovy and chile, and cook for another 3 to 4 minutes over medium-high heat, until the onions get soft and are beginning to caramelize. Add the capers and green olives and crushed tomatoes and stir well. Add the fish back to the pan and turn to coat. Cover the pan and turn the heat to low. Cook 3 to 6 minutes, depending on how thick the fish steaks are.
Uncover the pan, add the fresh tomatoes and parsley, cover again and cook for 2 minutes more. Serve hot or at room temperature.
I have cooked this with all sorts of fish, from catfish to sturgeon, cobia to codfish, lingcod to leopard shark; the original dish uses swordfish. You want a firm-textured fish. I bet this would be equally good with chicken or turkey or pheasant.