Chicken Piccata doesn't contain onions, garlic, or sage. Brown the floured chicken in olive oil, remove and set aside. To the pan drippings, add lemon juice and zest, white wine, a little chicken stock and capers. Reduce slightly then add 1 Tbsp. cold butter. Swirl to thicken the sauce. Add the chicken back into the pan to heat. Add a little more lemon juice and serve pouring the sauce over the chicken.
Ah, well much of the stuff I make contains those things, and so does my Chicken Piccata. I believe that nothing is absolute in cooking, though, and any rules are made to be broken.