Butterfly your chicken breasts, then season the insides with salt and pepper. Add goat cheese and grated parmesan cheese to one portion of the inside of the chicken breast, then add your onions, peppers, and garlic. Add several basil leaves, then close up the chicken breast. You can also tie the chicken breasts here to make them easier to handle and cook.
Attach a sage leaf to the top of each chicken breast using a toothpick, then season with salt and pepper.
To make your sauce, add onions, garlic, rosemary, and red bell pepper to the pan that you cooked your chicken in, then deglaze with white wine. Add a splash of Madeira, followed by your chicken demi glace. Bring it up to a quick boil, then strain your sauce to remove any solids. Next, return the sauce back to your pan (you may need to clean your pan first), and reduce it.
When your sauce has thickened a bit, add a knob of butter and incorporate it into the sauce. Add a few drops of lemon juice, and season with salt and pepper as needed. You might also add a pinch of sugar to balance it.
When your sauce is done, spoon it over your chicken breasts and you’re ready to serve.