Season chicken breasts with salt and pepper.
In a large skillet, melt butter over medium heat.
Add onions and sauté until translucent.
Stir in minced garlic and cook for another minute.
Dredge chicken breasts in flour, shaking off excess.
Add chicken to the skillet and brown on both sides.
Pour in chicken broth and bring to a simmer.
Reduce heat and cover, cooking for 15 minutes.
Remove chicken and whisk in heavy cream to the gravy.
Return chicken to the skillet, cover, and heat through.