In a large skillet over medium low heat, drizzle 1 tbsp of olive oil and allow to warm up.
While skillet is warming up, prepare chicken breasts. First, pat chicken dry and then butterfly them open. Season both sides with salt and pepper. Place in skillet and cook chicken on each side for 5-7 minutes.
While chicken is cooking, chop shallots into small pieces. Shallots are an amazing way to add an onion flavor without overpowering the dish. If your children aren't huge fans of onion, then shallots are the way to go. They have a much less potent smell and flavor.
Once chicken is browned on both sides, remove from skillet and place on a plate, cover with foil to keep warm. Drizzle the other tbsp of olive oil in the skillet and add in the butter as well.
When the butter is melted, add in the chopped shallots stirring often so they cook evenly and don't burn. While shallots are cooking, chop the fresh sage.
After about 7-10 minutes the shallots should be cooked enough. Add in sour cream and heavy whipping cream. Stir to combine. To thin out the sauce a bit, add in pasta water (if you are going to serve with pasta) or low sodium chicken broth. Add in sage and again stir to combine.
Place the chicken back into the pan and cover it with a lid or foil. Allow to simmer on low heat for 10 minutes, turning the chicken halfway through. This allows the chicken to finish cooking as well as moisten and combine with the flavors of the sauce.
Once chicken is finished. Serve immediately. Can be served over pasta or rice, or on it's own. Very tasty either way. Plate the chicken first and the spoon sauce over top, for extra garnish, top with a couple of whole sage leaves.