Heat oven to 200ºF.
Cut the turkey breast crosswise into 1/2-inch pieces. Place pieces of turkey, one at a time, between two pieces of plastic wrap. Spritz the meat lightly with water; spritz the top of the plastic wrap as well. Pound to no less than 1/8-inch thickness.
Season both sides of meat with salt and pepper and then dredge in flour. Shake off the excess flour. Set aside.
Heat the olive oil and 4 tablespoons butter in a large saute pan set over medium-high heat. Once hot, but not yet smoking, brown the turkey, about 1 minute on each side, and remove to an ovenproof platter. Place in oven to keep warm.
Reduce the heat to low and add the shallots to the pan. Saute until they begin to turn translucent, 1 to 2 minutes. Add wine and lemon juice to the pan and simmer until slightly reduced, about 2 minutes. Add remaining 2 tablespoons butter and whisk to combine. Season with salt and pepper, to taste. Pour sauce over turkey, sprinkle with parsley, and serve immediately.