Sprinkle both sides of the breasts with salt and pepper. Lightly coat the bottom of a 8 x 8-inch baking dish with vegetable or canola oil. Place the breasts in the dish in one layer.
In a medium skillet over medium heat, place 1/2 tablespoon olive oil. Add the mushrooms and saute for 2 to 4 minutes. Remove the mushrooms with a slotted spoon, and distribute evenly over the chicken. Add the remaining oil to the skillet; saute the onion and garlic until transparent, about 4 minutes, and place over mushrooms.
Combine the wine and sour cream; pour over the chicken.
Discard the oil and wipe the skillet clean with paper towel. Melt the butter in the skillet; add the crumbs and toss to coat. Sprinkle the crumbs over the chicken breasts. Cover the dish with foil, and bake for exactly 1 hour. Serve immediately.