Cut chicken breasts into 4 long strips. Season chicken with salt and pepper. Dredge chicken in flour and shake off excess.
In a large skillet over medium high heat, melt 4 tablespoons of butter with 2 tablespoons olive oil. When butter and oil start foam and turn golden add chicken and sauce for 3 minutes. When chicken strips are browned, turn and cook other side for 3 minutes. Do not over crowd pan, work in two batches if needed. Remove and transfer to paper towel lined plate.
Melt 2 more tablespoons butter. When butter is melted (See Note 4) add the white wine, lemon juice and chicken stock. With a whisk, stir and bring to boil, scraping up brown bits from the pan for extra flavor and breaking up any lumps. Add the capers to the sauce and taste for seasoning.
Chop the chicken into bite size pieces or leave as strips. Add the chicken to the pan, toss to coat and simmer for 5 minutes.
Make mashed potatoes. Divide mashed potatoes over the 2 plates and make a well in center of each. Divide the chicken into each mashed potatoes well and pour sauce over chicken and garnish with parsley and lemon slice.
Video
Notes
I used 10 chicken tenders, or use 10 oz breasts or thighs, chopped.
For a thicker pan sauce: Add 1 tablespoon of flour and stir to cook flour for 1 minute. Then add other sauce ingredients. By adding the flour to the butter and olive oil this will make what is called a roux, which will thicken the pan sauce when liquids like chicken stock and/or wine is added and whisked together.