Use a meat mallet to flatten the chicken breasts between two pieces of parchment until they are uniform in thickness, or about ½ inch thick. Combine the tapioca starch, salt and pepper and sprinkle the mixture on all sides of the chicken. 

Heat 2 tablespoons of butter in a skillet over medium heat. Once hot, add the chicken breasts and sear for 4-5 minutes on each side. Remove the chicken breasts and set them aside.

Heat another tablespoon of butter in the skillet. Once it is melted and bubbly, add the garlic slices and saute until fragrant. Add the chicken broth and stir with a spoon or whisk to pick up any browned bits off the bottom of the pan. Once the mixture begins to bubble, slice the lemon in half and squeeze the juice from half of the lemon into the pan and stir it in. Once the mixture starts bubbling, add your chicken back to the pan. Cook the chicken for a few minutes on each side until the internal temperature reaches 165 degrees. 

Add the capers and half of the parsley and fold them into the sauce. Once the sauce has reached your desired thickness (you can always add a little more broth if you want more sauce), remove the pan from the heat and add in the last tablespoon of butter and mix it into the sauce. 

Slice the remaining half of the lemon into thin slices and top the chicken with the lemon slices and remaining parsley and serve alongside your favorite veggie side dish.