Pound chicken breasts to 1/4-inch thickness between two sheets of plastic wrap. (Alternately, cut breasts in half horizontally.) Sprinkle both sides with salt and pepper, then dredge breasts in flour.
Pour olive oil into a large nonstick skillet and heat over medium high. Add chicken and cook 3-5 minutes per side, until chicken is done and golden. Remove from pan.
Add chicken broth, wine, and lemon juice, and cook, scraping up any stuck bits, for about 2 minutes. Remove from heat and stir in butter and capers.
Serve chicken with the sauce drizzled over and sprinkled with parsley.
Notes
If you would like to omit the wine, swap in more chicken broth.