Season both sides of the chicken breasts with salt and black pepper.
Heat olive oil in a large skillet over medium-high heat.
Add the chicken breasts to the skillet and cook for 5-6 minutes on each side until golden brown and cooked through. Remove chicken from skillet and set aside.
Reduce heat to medium and add minced garlic to the skillet. Sauté for 1 minute until fragrant.
Pour in the chicken broth, scraping the bottom of the skillet to loosen any browned bits.
Stir in the heavy cream, lemon juice, orange juice, lemon zest, orange zest, and chopped rosemary.
Simmer the sauce for 5 minutes, stirring occasionally, until slightly thickened.
Return the chicken breasts to the skillet and spoon the sauce over them.
Add the unsalted butter and cook for an additional 2-3 minutes, basting the chicken with the sauce until heated through and glossy.
Remove from heat and serve the chicken topped with the creamy citrus rosemary sauce.