Slice the chicken breasts in half lengthwise, pat them dry, then season them with salt and pepper to taste.
Whisk the flour, Italian seasoning, onion powder, and garlic powder in a medium shallow bowl. Dredge the breasts in the flour mixture, and shake off excess.
Heat a tablespoon of butter and oil in a large skillet over medium-high heat.
When the butter has melted, add the chicken and pan-fry for 3-4 minutes, then flip and cook for 2-3 minutes (how long depends on the thickness of the slices). Work in batches if using a small skillet.
Transfer the chicken to a plate and set aside.
Melt the other two tablespoons of butter in the same pan, and saute the onion and garlic for a minute or two until the onion is soft and translucent.
Add the wine, chicken stock, and lemon juice, and bring to a boil, scraping up any brown bits from the bottom of the pan for extra flavor.
Cook until the wine almost evaporates, stirring occasionally, for 3-5 minutes. Then reduce the heat to low, stir in the capers.
Add the remaining butter, allow it to melt, and stir it into the sauce.
Do a taste test, then adjust salt and pepper as needed.
Return the chicken to the pan, including its juice, and simmer 3-5 minutes.
Garnish with parsley if desired and serve immediately with pasta and parmesan cheese.