Halve the chicken thighs with a sharp knife. Working with one chicken at a time, cover the chicken thigh with plastic wrap and use a mallet or pestle to pound the chicken until it is thin
In a large heavy-bottom pan, melt 3 Tbsp of butter over medium-high heat. Add in sage and shallots and saute for about 1 minute
Preheat oven to 180 F. While the shallots and sage are cooking, get another large heavy-bottom pan ready and add in some olive oil. Coat each piece of chicken thigh with flour and pan fry for about 3 minutes on each side or until cooked through. Then the cooked chickens warmed in the oven while reducing the Marsala sauce
Add the Marsala wine and broth to the pan with shallots and sage. Bring it to a boil and then lower the heat to simmer and let the liquid reduce until about 1/2 cup, which may take somewhere about 10 to 15 minutes. Add the rest of the butter to the sauce. Taste and season with salt and pepper to your taste
Get a serving platter ready. Arrange the chicken pieces on the platter. Pour the sauce over the chicken and serve immediately