In a skillet or sauté pan over medium heat, melt 1/4 cup of butter; add the chicken breasts; sprinkle with salt and pepper.
Cook for about 3 minutes on each side, or until the chicken is browned.
Add the sliced zucchini and onions. Continue cooking, stirring until zucchini is crisp-tender.
In 2-quart saucepan over medium-low heat, melt 2 tablespoons butter; add garlic.
Cook for 1 minute, then stir in flour and cook until smooth and bubbly. Continue to cook for 1 to 2 minutes longer.
Add cream cheese, chicken broth, and pepper and continue cooking, stirring occasionally, until sauce is smooth and thickened. Taste and add salt, as needed.
Serve the dish on a bed of rice or pasta. Layer the zucchini and then the chicken breasts on top then pour some of the sauce over each chicken breast.