Butterfly each chicken breast, cutting horizontally into the thickest part of the breast almost all the way through to the other side (keeping the breast attached on one side).

Open each breast like a book and place 2 basil leaves in the center of each chicken breasts and top the basil with 2 slices of prosciutto. Fold the chicken over to enclose the basil and prosciutto and secure the filling with a skewer or toothpicks.

Season the chicken with salt, pepper and garlic powder on both sides. Spread 1 tablespoon of the flour on a plate and dredge each breast very lightly. Shake off the excess. Set aside.

In a large nonstick skillet over medium-high heat, melt 2 tablespoons of butter and oil. Add the chicken and cook for about 4 to 5 minutes or until the chicken is golden brown.

Turn the chicken over and cook for about about 3-4 minutes. The chicken will finish cooking on the sauce. Transfer the chicken to a platter and cover to keep warm.

Lower the heat to medium-low. In the same skillet melt the butter. Add the remaining flour and cook for 1 minute stirring constantly. Add the wine (optional) whisking to avoid any lumps.

Cook for about 1 minute. Slowly add the broth and lemon juice and bring to a boil. Let the sauce cook down for about 2 minutes to thicken slightly.

Return the chicken to the skillet, and cook over medium-low heat for about 2 minutes. Top each chicken breast with 2 slices of cheese. Cover the skillet and cook 1 to 2 minutes or until the cheese is melted.

Season with salt and pepper to taste if needed. Serve immediately.